<human>: I got into my first serious relationship along with my first sexual experience with this girl, who I had liked for a long time. Things were great, well, better than great, for 5 months. There were some oddities (e.g. one day I walked in unannounced to find another guy in her bed, under the covers...but we talked about this and settled it) and some frustrations (most notably, I couldn't get over the fact that she had many sexual partners before me, especially since she was my first), but I really did like her, a lot. 

After a while, though, our relationship became too much of a power game in my mind. I overthought everything, from casual conversations to our sex life, in order to try and "hold the upper hand" in the relationship. I feel as if she played the game, too, but maybe I was just overthinking that as well. This caused some constant worry, and probably prevented me from being myself, especially because I am not very masculine or "alpha," naturally.

She broke up with me unexpectedly one day. She originally blamed it on something petty––which drove me insane––but later admitted she had wanted to break up anyway. When I returned to get my clothes the next night, she was already with another guy––a mutual friend––both locked in her room and fooling around. She knew I was coming, too.

I didn't realize it at the time, but after some reflection, I now see how ridiculous it was that I was so caught up in this power game of our relationship. I regret it, though I don't know if that had anything to do with our breakup. I also now find myself generally distrusting people, notably women, as a whole. I mean, she was a sweetheart who had all my trust. I never would've guessed it to break down like that.

Two questions: How can I prevent any future relationships from turning into a power game? And how do I prevent any anger/distrust in  her from leaking out into other women/relationships in general? I find it too easy to apply a blanket statement based solely on her actions. Am I crazy?

Summarize the given text in a few sentences.
<bot>: Once-great relationship. Over time, turned into a power game. Breakup had me distrusting people, mainly women, in general. How do I prevent these two things going forward?