Venting/advice

So basically i've been with this guy for about 6 months. In a way he was kind of a rebound but i love and care about him obviously. Before him i was with a guy on and off since i was 14. (I'm 19 now)  Ever since i was younger i always thought he was "the one" and i never knew exactly why. Something always pulls me towards him. This past year was so rough for us. He was talking to other girls and even took MY car to go see another girl. But even after all of that and how horrible he's treated me i still want him. He has no idea though. He thinks im moved on and happier than ever. In a way i am but i feel like i didn't really have any closure. I know i can't trust him but i just feel like i shouldn't let go? Anyways, he messaged my friend and tried to get in touch with me saying that hes going to the military in October and he just wants to talk to me. That was about 2 months ago and ever since then ive been feeling weird. My boyfriend and i have been having problems and i feel like im just not into him... I love him and have been through a lot with him in these past 6 months but i just have a weird feeling. But i know it would be a mistake to just leave him for someone who has put me through so much. I know he loves me and he actually shows it, i just have no clue what to even do or what to think at this point... We live together and the whole time im thinking about when im gonna be able to move out and have time for myself. I just dont understand why i feel like this... Someone help! 😞