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Families come in all shapes, sizes and, most importantly, dynamics, which can sometimes cause awkward even stressful situations on your big day. And, let's be honest, the last thing you want to do before you and fiancé say your I dos is come up with a new seating arrangement because your relatives don't get along. To make sure your wedding day goes smoothly and no one feels left out or offended, we asked Lizzie Post, etiquette expert and co-host of the Awesome Etiquette, how to deal with five common issues for families with complicated or nontraditional relationships.

1. My parents are divorced and have remarried. Whose name do I put on the wedding invitation?

"The wedding invitation is issued by the people who are paying for the wedding — whether that’s the couple, the groom’s parents, or the bride’s parents. It’s really the people who pay for the wedding that are listed on the invitation. If they want to extend the invitation to someone else and say, 'We would love to put your name as a host on the wedding invitation,' that is completely up to those people to do that.

Couples should really keep in mind the formality of their wedding. The more formal the wedding, the more they really want to make sure that the invitation is worded properly. If the wedding is casual, then using very casual wording is perfectly fine."

2. How do we seat our parents if they don't get along?

"Don’t seat them next to each other. I would forgo having a head table. Instead, have each set of parents seated at a table that has some of their friends or other family members at it. Do that with everyone — your sister, brother, so that it’s all spread out. That way you don’t have a table with a stepmom, stepdad, your sister, your brother, your grandparents and then, all of a sudden, dad and stepmom are all the way cornered at a different table.

As long as you’re not isolating just this one person, then it just becomes apparent that the bride and groom didn’t have family at their table and they mixed it up. Maybe they did a sweetheart table and it was just the two of them. If you handle it elegantly enough and with consideration about how people will feel once they see what the seating arrangement is, people genuinely won’t be upset."

3. I don't want to invite my fiancé's sister to be my bridesmaid. What do I do?

"If I am a friend or a parent of the bride or the groom, I would talk to her and just say: 'How much is this really going to affect you to have his sister standing next to you and possibly participating in some of the bridal events?' At the end of the day, most people are willing to say, 'You know what, she’s going to be apart of my family so I might as well extend the olive branch this way and make her feel good about it than not.'

This is a moment that you and your future husband are going to look back on and the question is: Is it going to be easier for you to look back on it and say, she is not my favorite person in the world but it made her happy and it kept a lot of things easier by having her stand next to me during the ceremony? Or do you want to look back and have her constantly taking digs about Oh, the wedding I wasn’t a part of…"

4. My dad and I don't have a good relationship. Can I have someone else walk me down the aisle?

"You can choose anybody — your stepdad, brother, uncle, a best male friend. You can have your mom walk you down the aisle. It’s really entirely up to the bride who she feels would be a good person to do this.

A lot of fathers know when they don’t have good relationships with their daughters. Maybe she can consider doing something special with him if she wanted to. And if not, she can just acknowledge the fact that this is how it’s going to be and say, 'I’d love to have you at the wedding, dad, but we know we are not close and I didn’t think it was appropriate to have you walk me down the aisle.'"

5. My fiancé picked a best man that I don't like. What should I do?

"The bride really has to let her groom choose his best people. She can’t dictate who that man is. She doesn’t get to tell him who his friends are.

Maybe he is just the rowdier, still partying type, and she really wants to have an elegant, classy wedding. In that case, the groom might talk to his friend and say, 'Listen, the bachelor party and the after-party would be great places to let loose and have fun, but the actual wedding itself, because of all the family that will be there, we are really trying to keep it civil, elegant, and classy.'"