It's a sad but inevitable reality in many families that some members won't be supportive of same-sex relationships, and that they will be even less supportive of same-sex weddings.
So what should you do when it's time to make up the guest list? Should you invite these relatives, even though they've hurt you in the past and might do so again? Should you not invite them, even though they are family, and though they are important to you in other ways?
There are widely varying opinions on this. Writing for the New York Times, author Steven Petrow had this to say:
Take the high road and invite all your family members, even if you think they don’t support your relationship. After all, it takes an awfully cold-hearted person to sit through a wedding ceremony and not be moved—if not to tears, at least to acceptance. Consider this a unique opportunity to change some hearts and minds.
Petrow believes that there's no way to get wedding participants to sign a pledge that they will be nice. Instead, he advises that you simply phrase your invitations to say, "You are invited to come and support us as we commit to our life together."
Many others take a different view, basically saying that anybody who isn't happy that you are being married shouldn't be there. One moderate approach is to give people a second chance by inviting them to the wedding, but to make it clear that you don't want to hear another word of criticism or negativity of your life. A more extreme approach is to choose not to invite anybody who previously proved to be critical or unsupportive.
If you don't take a position on the extremes (either inviting everybody, or not inviting anyone who was previously unsupportive), you will wind up with some difficult decision to make.
Ultimately, ask yourself how you would feel if you walk down the aisle and you see that person standing there? Would you be glad and grateful that they are a part of this amazing experience? Or would your stomach sink because of what you expect they will say or do? At the end of the day, this is your special day, and you deserve to be happy, so keep that in mind when dealing with unsupportive relatives.