Are you expecting them to honour your union if you don't honour theirs? if not why invite them? BTW I am not married, my partner and I made a personal commitment and that is all I believe is necessary. The wedding thing in a church is flim-flam. The ceremony and certificate itself is a subjugation of the personal to the state. What actually matters is the feasting and the people you choose to share it with. Which seems to be the bit that people are compromising.