help me forget my girlfren past

I dont know if this sounds too immature for some of you guys this is what I am going through right now. If anyone had similar issues in the past please share !! I know my gf for over 5 years now. We have been in relationship for over 4 yrs now and during our initial days...I asked her if she had any boyfren before me, and if she had any physical relationship with him. Back then she told me she had a bf but she never went out with him. Not even in a restaurant. But she said they used to study together and thats how they fell in love. She said he didn't even kiss her. I know she is shy and doesn't want to let everybody know about her relationship. Therefore I believed everything and was ok.with it. It went very smoothly for almost 3 yrs after that day. However, a while back I don't know what went wrong. I started visualizing her past with that guy (her bf) who I had met once and had seen some pictures in facebook. I started digging deeper...using her emails, facebook accounts, asking other friends of her, and sending fake emails to her just to know if I could find something. Finally, I was able to get her trapped in a fake email and she explained me what they did. It was nothing big, just some kisses, hugs and touching. While she expliained it, She cried and said She tried to go away from me many times and since she couldn't do that, she finally prayed to god that she would like to die before she can marry me. I know she doesn't lie. She never lied me with any other things for such a long time. It was only this secret which was so much hard for her to express kept her being emotional for a long time. Since she was crying a lot and asking me to leave her as she didn't want to ruin my life, I had to explain my past as well. I had similar incidents with my cousin so I explained it to her as I thought it would make her feel good since both of us would be on the same floor. I never had sex with my cousin, it was just some kisses and touchings. I never had any other girlfrens before and I am still a virgin. Ya even after being in a relationship for over 3 yrs we never had sex. That is why i believed her becasue of her nature. But now I am still jealous about her relationship and still think they might have sex and she is just hiding it just to not loose me. I tried asking her about any sexual encounters after the day she expressed herself, but she was really mad. She said ramayan ma ta sita lai prove garnu parethyo ram lai parethena...malai tha cha timlai ajhai ma mathi biswas chiana bhanne !! I didn't have any answer to this !! I know its long but wanted to share with you guys to get some answers...I do believe she never had sex because of her nature and simplicity...but i also think if it all depends on the guy she was with...if he insisted her to do it ................