Want what i cant have

Basically I'm crazy about a girl who is with another guy. Here's the whole story:

One of my close friends, if not my closest, has a younger sister (J) that I've always been attracted to, but never really gotten to know. She had been with this guy for 3 years, until this past summer when he got real depressed and dumped her. Unbeknown to me, she sat around for 3 months miserable because she did nothing wrong. On a side note, I've never understood how they made it 3 years since he paid no attention to her whenever they were out together. Anyway, one night she came out to the bar and we hit it off and talked all night. We exchanged numbers and began texting the next day. For the next 3 weeks, we saw each other everyday, and were basically "together" without the title. The only problem was that she was dragging her feet about getting her stuff out of his apartment because she still loved him. He eventually changed his mind and told her he wanted her back. I often wonder if it was because he knew about me. So she went back, and I told her we couldn't talk anymore, which made her cry and tell me she had feelings for me. Her sister had to step in and tell her to stop calling and texting me. It was horrible because I was attached to her and didnt want to let her go, but I wanted her to be happy.
About a month later, I started dating someone new, but was still thinking about J. I figured it would fade by spending time with my new gf, but I was wrong. J even called me one night and told me that she still thought about me, but hoped things worked out with my new gf. So I started seeing a therapist, and have continued since december, to try to get over J. I never really connected with my gf and ended up splitting last week, and I'm still thinking of J.
J's sister forbids me from trying to steal her away from her bf, but my therapist thinks I should atleast see if anything is still there. I don't know what to do anymore because its obviously not just gonna go away. I wanna talk to her, but I don't want to be stuck being friends with her either. What should I do?

Tell her how you feel and let her know you want to be more than friends. If this is the girl you want to be with i think you at least owe it to yourself to let her know how you feel. If she doesnt feel the same move on and respect her relationship but in the end at least you'll know you tried. If you tell her she may not end what she has right away but in time knowing how you feel she might. On the other hand just because you didnt connect with your last girlfriend doesnt mean you wont with the next. I say give it a shot tho. I hope this helps

If she's still dating the other guy, what can you do? Is she going to wait around for you to come save her and drag her away from a relationship she chooses to be in? Maybe she needs more time to completely detach herself from the guy she is dating, and if it continues at the rate it's at. Most likely he didn't learn anything and will be back to mistreating her soon, just wanted her back out of loneliness. That's just speculating, but when most relationships are broke, they are hard to fix.

She has to ultimately choose her own destiny. You aren't a completely proven guy in her mind yet no matter how much you have hit it off so she is going to be afraid. But who is she to continue to stay with somebody that mistreats her and is unhappy? I know we can be very blind in a relationship when we care about somebody, but life's a learning process and some lessons have to be learned the hard way. I don't mean to sound cruel, I'm speaking from my own personal experience as being dumped and learning it by losing her completely. The lesson sticks.

I would say if she contacts you next, you let her know how you feel but that you can't be there to support her if she wants to be with him. I know it might be difficult and you care about her but you can't really hold her hand through this. She has the best of both worlds, her comfort with her current guy and the emotional support from you. You gotta think about yourself too and what this is doing to you.

She can't possibly be mad at you for it. You will be able to find happiness with somebody else and if she decides enough is enough, guess who the first person she will talk to is? Doesn't that sound like a win-win?

tell her you love her and you want to be with her, and let her choose who she wants, otherwise you'll never know.

if she rejects you then at least you can make steps to move on knowing she dosent really want you, but if she dosent reject you then happy days.

it has nothing to do with her sister, its a short life, you should try and get what you want.

Ok you didn't mention ages, but I'm guessing that you are all pretty young (and no I don't mean that to be an insult). It sounds like either her current bf is her first, or she is a glutton for punishment. In either case you can't persuade her to leave him. Often those people stick around and endure the abuse for long periods of time. Sadly it often ruins them as a person in the process, and they have all sorts of issues in their future relationships. Follow kisswithafist's advice. If she doesn't leave him soon, then you need to find a way to move on. I'm sure your therapist can help you with that once you know what she wants. And whatever you do it has to be one or the other (you or him). Don't allow her to talk you into anything else, with the exception of her leaving him and having a little time before dating you.