As a pastor, here's what I'll say - funerals and weddings bring out the best and the worst in people, especially when it comes to families. When it comes to a wedding day, here's the advice I offer to a couple - invite the people you want to invite. It's your day. Not your parents day, not your friends day, not your relatives day, not uncle so-and-so's day. Your day. These are your memories. You invite who you want to be there. You can listen to other people and their suggestions, but when it comes down to it, you make the decision. Don't let others ruin the day by holding some kind of guilt over you either. Tell them to stop. While they may have made a different decision, you made the decision you made. It's complicated and they have no idea what it's like to be in your shoes. If they really cared about you, then they would just be supportive of you and your fiancé and your life together going forward.
There's two different types of families - there's the type you are born into that you didn't choose, but you can choose how much time you can spend with them even if those decisions are not popular, and there is the family that you can choose based on spending time with people you love. The second type of family is often more important than the first and often far more healthier.