Some of your negative thoughts might just be temporary (and are just thoughts unless you take action or say something based on these thoughts). When I have negative thoughts about someone, I try to not immediately react (when I do react immediately, sometimes I regret it). If you have grown apart from your friend, it is OK, sometimes it happens and hopefully, you can eventually think more about what was good about your friendship but if you have changed/grown apart, it's OK. Given your history with him, I think you should at least send a card congratulating him. He may think of your friendship in a different way than you do. I also wanted to mention that my husband is 6 and half years older than I am and we have been married for more than 32 years so an 8 year age difference doesn't seem that bad to me though since she is not 20 yet, IMO, she is still maturing and learning about herself. In any case, it's their life and your opinion probably won't change his mind.