She likes/loves me but continues with her Boyfriend?

Well, this story is kind of long and ill do my best to write it as understandable and coherent as possible.

I once had a girlfriend in highschool and also I was very close with her bestfriends, after we broke up one of her friends and I began talking to each other, we were both single at the time and texted each other regularly (we had chemistry & our mentality was almost similar), she once started seeing someone else and so I got jealous at her and blocked her from everything (she got upset about it), and so we didn't talked to each other for some time.

Last year I was in my Senior year (I was 18 at the time) of HS and she was a Junior, I was alone in one of the hallways of school and saw her, at the moment I was with someone else and she was having a boyfriend(4 months),she then reached up to me and told me why I blocked her this and that and said that she missed me a lot, after she was done she kissed me and left, I texted her (she added her phone on mine when we were talking) saying that we should meet up again after she was done with class, we made out at school and had a conversation, at the time I wasn't very in to her since I had a GF (and already cheated on as well as her that day.)

At summer (2015) I blocked her again because I was with my GF and was afraid she would see my texts of her in my phone.

Current year (2016) I contacted her again in April, shes now with her BF for a year now and she loves him without a doubt, she told me she was very mad at me for blocking her and that she missed me a lottt and kept contacting me either way.

Im finishing my first year of college and since she lives near it we decided to meet each other (we kissed and made out AGAIN) I can say she still likes / loves me? And went out on a date a few weeks later where we had our intimate moment, she gets jealous and mad when I talk to other girls and I do the same with her BF, Shes the one who most of the time texts me first and I KNOW she likes me because she told me (Looking at her behaviour shes crazy for me)

And I dont know what to do,

1. Should I keep going on with her until she leaves her BF

2. Or leave due to the fear shes planning a revenge on me for leaving her multiple times ( I know I was an asshole)

3. Bring out an Ultimatum

I think Im falling for her but Im not sure about it for the fear she'll also cheat on me.

We both have this amazing chemistry and no matter how bad the fight is we still fix it, I don't know wtf to do Suggestions?

P.s We both want to be in a relationship but she told me she doesn't trust me because I told her I don't trust her (obvious reasons). Im not sure if shes playing with me or what.....