I feel Stuck.

*WARNING THIS IS A LONG ASS POST*

So I been with my bf for about 3 years. Last january we split bc he cheated on me with a 15 year old and he was 18. Then he apologized because he told me he realized how bwd it broke my heart. Well

This past January I left him because things were not looking good in our relationship he stop putting in effort and started showing less interest. Although he wouldn't admit to talking to other ppl I knew in my heart it was happening. Sure enough 2 weeks later I had found out from October-January he had been cheating on me.. It was horrifying. The details literally broke my,soul. About a month later he started trying to wiggle his way back in and I didn't really know too much other than he had cheated. While we were split he would msg me behind her back I thought this was wrong so I stopped. Then hed get mad and compare me to her. My body to hers whatever it was. Then he stopped and seemed legitimately sorry. So I took him back because I've loved him since I was 15 years old. But then when we were rekindling things he told me that when he cheated they had sex NINE times. Mind you we're 18 this was some sweaty 30 year old slut he met at the gym. I call her a slut because she KNEW about me and even threatened me later on down the road. She became obsessed and stole my pictures from my Facebook and told him she was "willing to get augmented" so her nose cheekbones and breasts (I'm DD) resembled mine. I found her IG and in posts she talks about the augmentations. So back to what I was saying. After we got back together she harrased and stalked him. Then I guess she stopped? But now we been together 2 months and things are just not the same. I feel like the only time he's interested in me is when its about SEX. Before her. I was the first girl he ever slept with in September of 2016 we finally had sex. A month later he started hooking up with her. Now I'm just suspected of everything and I feel like I'm just an object to him. He never asks about how I'm doing unless it somehow effects him. I've told him how I feel and every time I try to talk to him he just says "baby you're so sexy " See everything is about SEX. He never is interested and if I look good when he's not around or if I want to do something for myself he gets super jealous. Like im not allowed to have guy friends. And the only time he is really sweet to me is when he's threatened. IDk how to leave when I do he finds me. Friends have told me he's narcissistic. When I asked him about his abusive behaviors and him constantly talking about his ex he used to compare me to her all the time. Now I just feel like he still is even though he doesn't say it. Sorry for this long post. I need step by step help. Please. Also I just moved 2 he's away for college. So now there's this aspect. And he had poor communication skills so everything is double Complicated!

It seems like every time I catch him cheating its from October- January. Is this weird or ?? What are your guy's thoughts??