I am in the same boat and I have to say, inviting someone "secretly" is not fair to you or the person you want to invite. You are not going to be able to please everyone. Feelings may get hurt, but in the long run "friends" will understand, especially if the cost falls on you and your fiance' alone. I am actually sending out cards to the people I wish I could invite but know I can't. I will tell them how much they mean to me and if I could invite the world, I would. Hopefully they will understand