Stuck and unhappy

I am in need of some advice. I am a female, and a junior in college. I have been straight for my whole life. I have had boyfriends and had sex with guys and have always been comfortable and confident with my sexuality. In my freshman year of college, I met a lesbian (we'll call her Morgan for privacy reasons), and we quickly became best friends. After hanging out for a while, she told me that she was in love with me. We hooked up, and I wasn't sure how I felt about it. I decided to give it a try because hey, isn't college a time to experiment? and also because I couldn't imagine hurting her and saying no when being with a woman is something I have never tried. So we started dating. In the beginning it was good. She treated me very well, and I thought this might actually be for me. Flash forward to two years later. We are living together and going to the same college still. I am absolutely miserable. She is insecure and doesn't trust me. She is clingy and has severe separation anxiety. I cry every time we have sex and I cringe when we kiss. I can't stop feeling this way even though I've really tried. I think what it boils down to is I am just not a lesbian. I miss sex with men so much, and I don't find anything about any woman, including Morgan, attractive. When I started dating her, I told myself that it would be enough to love who she is and how she makes me feel and how she treats me. I'm afraid it's just not enough. I have tried so many different ways to break up with her it is unreal. I am so deep in this mess that I can't get out. She is so attached to me that any time she feels me getting distant or being unhappy, she cries and bawls and reminds me that I am the only reason she lives. I am the type of person who cannot stand to make others unhappy, so I can't break up with her when she does this. Her family loves me and talks about marriage. All of my friends here at college are her friends too. I know they will turn against me if we break up, and I don't know if my mental health can stand losing all of my friends and being isolated in college. Also, Morgan and I live together in a legally bound lease. If we break up, we will still be living in the same house. I am so miserable and not who I want to be. I just want someone else's perspective on the situation. What should I do? Is it worth it to crush her and lose all my friends and be unwanted in my home just to get some of my happiness back? I can't keep living like this, but I don't know which situation would be worse.