Your big day is one of love and bliss, but most weddings also come with a hefty dollop of tense exchanges and awkward moments — a sibling scuffle, an unenthusiastic bridesmaid, a delicate discussion about who’s paying for what. Defusing these conflicts with grace is a must.

After all, “a wedding is a precedent-setting event, and the choices you make set the tone for future relationships,” says Anna Post, an etiquette expert at the Emily Post Institute. Here, she and other manners mavens share solutions to 14 common wedding-related dilemmas and tell you how to keep your cool when things get heated.

Dilemmas and Solutions
1. Fashion is not your mom’s strong suit. You’re worried she’ll show up at the wedding wearing something tacky or inappropriate.
Seek the help of a third party. “Ask her to join you for an afternoon of shopping, and use a personal shopper or sales consultant to take the pressure off,” says Karen Bussen, author of “Simple Stunning Wedding Etiquette” (Stewart, Tabori & Chang; 2008).

She’ll be more likely to accept fashion advice from a professional. If she still ends up picking something completely hideous, keep your disappointment to yourself: “In the end, a happy mother, wearing what makes her feel great, is much more important than a perfect photo opportunity,” says Bussen.

2. His parents aren’t contributing financially, but his mother still insists on having a say in the wedding planning.
Head her off by asking for her help in small, specific ways — such as deciding on the seating arrangements for her family’s tables or designing a groom’s cake with her son, suggests Elise Mac Adam, author of “Something New: Wedding Etiquette for Rule Breakers, Traditionalists, and Everyone in Between” (Simon Spotlight Entertainment; 2008). “If you didn’t plan on a groom’s cake, this might be the moment to consider it,” notes Mac Adam. And remember, if your future in-laws are hosting the rehearsal dinner, your mother-in-law automatically gets as much control over it as she wants.

3. Your parents are paying for the wedding, but they want a very different event than what you and your fiance envision.
First, express your gratitude. Then, explain your preferences in a non-defensive way. “If you emphasize how pleased you are, it will be easier for people to see why you like the things you do,” says Mac Adam. Then try to compromise. If you want 40 guests and they want 150, pick a number in between. If you’re set on a simple wedding and they want something more elaborate, Mac Adam suggests giving your parents free rein over some creative elements, such as the invitations.

If the list is loaded with so many of their invitees that there’s little room for yours, offer to contribute some of your own money in order to include more of your friends. If all else fails, though, you’ll need to let them do it their way, unfortunately — or foot the bill yourselves.

4. You’re not keen on asking your fiance’s sister to be a bridesmaid. You barely know her.
“You don’t have to ask her, but for the sake of family harmony it’s best to make every effort to include his siblings,” says Sharon Naylor, author of “The Bride’s Diplomacy Guide” (Adams Media; 2007). “Don’t think about now. Think about the future — when you’re at his family’s Thanksgiving, and you and his sisters have great wedding memories to share.” The one exception: If the sibling — either yours or his — strongly and vocally disapproves of your union, you may, without guilt, leave her out.

5. You and your husband-to-be are vegetarians. Your families are decidedly not.
Whether you avoid animal products, alcohol, carbs, or anything else, “your wedding is not the time to try to convert people to your way of living,” says Mac Adam. The trick is to be true to your beliefs without making guests feel deprived. For example, rather than serving seitan, tofu, or other unfamiliar foods, consider a non-meat pasta. Or offer a choice of vegetarian and non-vegetarian entrees.

Mac Adam recalls one bride whose parents wanted to serve a kosher meal, although only a handful of guests required it. The bride hired a second, kosher caterer to prepare that food. “There is usually some sort of middle ground,” Mac Adam says.

6. In lieu of six toasters, you’d prefer money for a down payment on a house.
“You can never ask for money,” Naylor says. Your mothers and your maid of honor may, if asked for gift ideas, let guests know you’re planning to buy a house and you would love something that would prepare you for your future home. But whether people choose to give you a check or a set of socket wrenches is completely up to them.

7. Your maid of honor is less than enthused.
You could “fire” her, but it’ll likely end your friendship, so try talking to her first. You may end up cutting her some slack. “She might be so overwhelmed with work or life issues that her wedding duties are taking a back seat,” says Mac Adam. “Another option is to let her step down of her own accord. You could say, ‘I don’t want to force you to do anything that makes you unhappy, so please let me know if you’re not up for this. I won’t hold it against you.’ ”

8. You’re inviting friends from work to the wedding. But you’d rather not invite your boss.
“It all depends on the size and location of the wedding and the size of your department,” says Mac Adam. If you’re throwing an intimate destination wedding, it’s unlikely that your boss would be insulted to be left off the guest list. But if you’re throwing a rather large affair and work at a small organization, it’s polite — not to mention smart politics — to invite the head honcho. “A courtesy invitation can’t hurt,” explains Mac Adam. “And your boss will be happy to have been thought of.” Finally, don’t worry that it will be seen as a ploy to score a present; most managers, regardless of whether they’ve been invited, give wedding gifts to their employees who marry.

9. You know exactly how you want everything to look at your wedding — including your bridesmaids. You’d like to dictate their entire outfits, down to the earrings and hairstyles, but you anticipate resistance.
It’s fine if you want to direct the aesthetics of your wedding; it’s not if you end up tyrannizing. Your bridesmaids are not your subjects. “Consider narrowing down your preferences to two or three choices, taking varying budgets and body types into consideration,” counsels Bussen. “Then ask your bridesmaids to make the final decision. This gives everyone the satisfaction of having participated in the process.” If you insist that they wear a uniform accessory (a particular style of shoes or a certain pair of earrings), “you should probably pay for those items yourself and make a gift of them,” Bussen says.

10. You don’t like your fiance’s old college drinking buddy and are worried that he’ll ask him to be his best man.
In this case, the decision is not yours to make. “Best friends are almost like family,” Post says. “How would you feel if your fiance didn’t want your best friend as your maid of honor?” For the sake of your marriage, try to learn to appreciate his closest pal. “After all, this person has probably been a part of your groom’s life for a long time — and is likely going to continue to be,” Post says. If you still want to persuade your groom not to ask him to be in the wedding party, discuss with your fiance other ways of including his friend, such as asking him to do a reading (of your choosing, of course) at the ceremony.

11. You don’t want kids at your wedding and want to convey that without offending your guests.
Let your invitation do the talking, Post says. Let’s say you’ve chosen not to include kids younger than 5, and your friends have an 11-year-old and a 4-year-old. You’d write the friends’ names and the older child’s name on the inner envelope, indicating that the youngest isn’t invited. If you’re worried guests won’t get the message, call beforehand. Says Post, “You can say, ‘We just sent the invitations and we’re excited to have you join us, but we’ve decided not to include young children. I wanted to give you advance notice so you have time to find a sitter. I hope you can make it!’ ” Don’t grant any exceptions; that would be rude to guests who’ve abided by your wishes.

12. There are already three bridal showers being held in your honor. Now someone else wants to throw you another one.
You may decline the offer if the same guests who would be invited to this shower will already be going to one of your others. In fact, says Post, if that’s the case, you should decline. “You cannot have lots of showers with all the same people. It’s an unfair burden on your guests,” she says. (However, you may invite your closest family members and friends to multiple showers, but they needn’t bring gifts to each one.) To bow out gracefully, Post suggests either inviting your would-be hostess to one of the other showers (keeping in mind that shower guests must always be invited to the wedding) or offer to take her out to lunch so you can chat and catch up.

13. You arrive at your reception site early and notice the centerpieces are not what you had agreed on with the florist. You consider a showdown with the vendor.
Unfortunately, this isn’t a rare occurrence, which is why it’s important that your contract have all the details in writing. Even better, have a picture taken of the final chosen design, suggests Bussen. “On the wedding day, if the issue can’t be corrected on-site, ask your photographer to be sure to document the centerpieces,” she says. “Then let it go, and enjoy the happiest day of your life!” You wouldn’t want an argument to cast a pall on the rest of the occasion. You can lodge your complaint and attempt to get a refund — once you’ve returned from your honeymoon and have your photo evidence in hand.

14. You have a few relatives who rather enjoy misbehaving.
Well, it wouldn’t be a wedding without at least one loose cannon — the uncle who drinks too much, the overemotional mother, the cousin who needs to be the center of attention. You can’t control other people’s behavior, but if you’re worried, enlist a trusted friend to keep an eye on the troublemaker and nip any developing scenes with a well-timed, “How about a dance?” At Naylor’s own wedding in April 2008, “We asked my husband’s cousin if he’d act as the bouncer. Nothing happened, but it made me feel better.” Then, focus instead on celebrating your new union.