<human>: Here goes for my first post....

  I've known this girl for three years prior to us dating, we've been dating now for about two years. I'm [m20] she's [f18]. its gotten to a point where I feel as though the relationship is at a stand-still. We just argue all the time and spent very little time together mostly because I don't really enjoy our time together anymore. We broke up once before (my doing) and then got back together. I haven't left for good because I do love her, at least I think I still do and she says she loves me. I also feel like we're really different people.

   I recently found out that she kissed two of her guy friends. Once when we weren't together and once when we got back together. I should note this happened months ago and she just recently told me, even when I've asked her if there's stuff I didn't know about in the past. she told me that the guys kissed her and she didn't want it and told them to back off. I'm still not sure if that's all there is to her story or if there's more. At this point I'm not sure the relationship is worth it or if I'm just forcing myself to be with her because I think I love her and that im obligated to be with her for some reason.

Condense the text into a few key points
<bot>: Ive been seeing a girl for a long time and the relationship is starting to go downhill. She cheated on me and waited to tell me and I'm not sure what to do or if I still love her.