M21 This is how I became a cuckold for my girlfriend [first time]

My girlfriend and I have been dating since we were both 15 in highschool. We were both super innocent and didn’t even lose our virginity to each other for until we were 17. So it was a big deal for us and we were both super proud to be each others only body. Which wasn’t the case for all of our friends and we always talked about how amazing it was for us. We stayed together and did long distance for our first year of college. While I was away I ended up kissing another girl and she found out. We obviously broke up but kept talking to try to get back together but something changed when we weren’t together. She wanted to go on other dates which obviously made me super jealous but I couldn’t say no. She would ask so where’s the line, what’s too far?? When going out of on dates and I never knew what to say. I knew she was just doing it to make me jealous but maybe it was more. She started fucking other guys and was doing it so much I think it became less about making me jealous and her just really enjoying it. But I did get soooo jealous I also never did anything with any other girls. We eventually have gotten back together but it’s totally different now. She now has all of these sexual experiences and to be completely honest Ive never been good at sex and have a really small penis. So now we’re back together and in college. We have a very different type of relationship where she kinda gets to sleep with whoever she wants. Ive been more understanding once shes explained how she felt after I kissed another girl and how she felt after having good sex for the first time but it’s our crazy sex like no one knows about