Okay so I've had one girlfriend and I'm 21 we dated for 4 years about. To start off I love this girl no matter what. She will always have a place in my heart. However in 2015 I went to basic training for the army and at the time we were dating for like 6 months. Come to find out she ended up cheating on me with a "friend" of mine from high school. Who by the way was also in the army. They didn't sleep together but they went on a date and shot and made out before she decided that what she did was wrong and broke it off after a few days. I found out and should have broke up with her then and moved on but my first love it was hard to do that. So we dated for another 3 years pretty well with some problems but she never even remotely showed signs of doing anything again. So then she leaves for the army and its training. This time we broke up before she went so she could focus on that while she was there. We had full intentions to get back together afterwards. However a few days before she left I got drunk with my friends which she didn't like and decided going to a guy friends guy friends house was a good idea. This time she ended up sleeping with him. We weren't together technically but it still hurt because for the longest it was kinda a special thing to be the only person we've both slept with. So that happened and I didn't find out until she got back. The whole time she was gone she started becoming distant and flirtacious with other guys there. She still talked to me every day but made it clear now she doesn't know what she wants. I guess she knew what she did was wrong and was trying to distance herself from me to make it easier when I found out. However my dumbass self heard this all and decided to not just remove her from my life. Now she's back and wants to be together again but now I'm pretty sure I dont. I know I'd be sooo stupid to go back and i should experience life more and forget about her but I don't know it's hard. What should I do?