Yes, I feel like a horrible person. But:
My friend got married a couple of years ago. Initially, she had quite big plans (wedding here and in Canada where she's from, big dress, etc. etc.), but she had to move the wedding forward a few weeks because of her job, and along the way she ended up with something a bit simpler. I was there and, with another good friend, we organised a hen do and (on the bride's response to us asking what she'd like) paid for someone to come and do her hair and makeup, and we did all the other things you do. It was a small wedding party - family and close friends - although I thought it was lovely.
At the time, she said she might organise a reception in Canada for friends from home who hadn't been able to make it. It was clear at this point that I would not be able to travel for this, for what it's worth.
Roll on two years, and I have got a save the date card for her 'wedding' in late 2017. Which, apparently, is the 'proper wedding' she thinks she didn't get. There is a link to a wedding website, a large gift list (including the suggestion guests donate for people back in Canada who can't come over here), and an RVSP. Within a week I had a chase-up phonecall asking if I'd got the Save the Date.
I am in two minds here. On the one hand, she is a friend, who ended up having a much smaller wedding than she obviously wanted, and she will clearly be upset if I don't come. On the other, I feel a bit treated as a cash cow/prop in her weddings, and - if all goes smoothly - I will have a still quite new baby when her second wedding takes place. We're not announcing the pregnancy for another six weeks, but even if we could say that was the reason for turning down the invitation, I still feel fed up. Am I being unfair?