Current boyfriend meets girlfriend ex-boyfriend(first boyfriend)

Folks,

Need your experience. My girl invited me to go her friend´s birthday party. My girl used to date her brother. That happened 15 years ago, when both of them were 14 or 15. He was her first boyfriend and she lost her virginity to him. I was full of shit in my head before the party ( it happened last weekend). But I tried to put that aside and went with her. At the party I end up talking about work with the guy, and he is actually not bad (Not that we will become best friends now), but still a bit weird felling remains: You having first time is a big moment in someones life and she did with him, they had a relationship and everything. I can not tell exactly what it is, but it is weird.

Question: Did I do it right going to party?

What is this shit that I am felling?

How Do I make this weird felling goes away?

Thanks…

I actually have a lot of experience with this. One of my ex-wives is a good friend of mine... and now so is her husband, and she and my wife are friends.

You did well - that's a very adult attitude to take. I don't know what the feeling is that you're having, but I'd guess second-guessing yourself.