a to much sensitve case please help me ???

hi guys , i have a friend from last 2.5 years. she is my best friend and before 2.5 year i have my own girl friend and she have own boyfriend but she like me on that time but not clear me. after six month i have breakup from my girl friend then e both as talk like a good friend. but from last i am also like her to much also love her to much and she is also to me . sudden i thought that she can take care of my family if she be my wife. and before some days she propose me to marrige with me and she is frustrated with his boy friend from last 2.5 years.and she want to marry with me and finaly she give me a propose for doing marry but last 2 days she clear me something that i have so serious problem and can't marry with you. so iasked what happen then she tell me that by mistake i was make a body relation with my boy friend and she say to much sorry and he feel that this is big mistake. and she is telling me about this today. so guys please help me i have to marry with her or not ????


and if i will not marry with her then she say i will marry with my boy friend and divorce him by any reason. i dont want to leave with him a long time if he (her boy friend) is not left me then she will suicide.

guys please help me i dont want that she bring the paid and frustrate with her life . she also realize this mistake and promise to never do this ..

i am in to much tension and unable to find any solution