My gf (24f) and I have been together about 2 years now in what I thought was a pretty happy and open relationship, but last week she told me she once made out with one of her friends when she was in highschool (another girl) and when I asked her if it was a drunk thing or if she was in a curious stage, she laughed and said she tried it a few times and it was fun but she knew she liked men so she stopped and hasn't really thought about doing it again. I was a bit blindsided by this given the fact not once have I even felt like hanging out with one of my bros and making out with them to see if I liked it or not. And multiple times! I feel like for women it's a different experience but I still see it for what it is. To clarify I don't plan on leaving her or making a big deal about it, but it's something that's sitting there in the back of my mind that seemed a little weird.