Overthinking an event and ruining our relationship

Hello

I am currently in a relationship with a girl I really like. She is however more in love with me than I am with her, mainly due to me overthinking a situation that happened a few years ago.

We learned to know each other when she initiated contact with me and my friend. I didnt talk to her at all during the evening, or any of her friends. As the night went on she approached my friend but he rejected her. Nothing happened. The next day, when she learned to know me, she felt something and she admitted she had fallen in love with me as soon as she learned to know me. Later on, I became the first person to have sex with her.

Since then, she has been crazy about me. Before we got into this relationship we had known each other for more than 3 years and a few months ago it got serious. She had changed and now I cant imagine myself being without her.

What is bothering me is that I spend all day thinking about if we are meant to be or not. I keep thinking that if my friend didnt reject her they would be together right now and she would be totally crazy about him instead. I keep feeling that I was the 2nd choice and that it was up to my friend whether we would be together or not.

I try to convince myself that theres a reason shes with me and not with him. But then it feels like the only reason for that is because he rejected her!

I am still the only one she has slept with although its gone more than 3 years. She has had other partners during these 3 years, and I dont even care about it. The only thing that is bothering me is this event. Its ruining our relationship and everytime I think about her I get into this negative mood. Maybe it has to do with the fact that I ve been hurt so many times before?

Why I am doing this?

What should I do to be able to open and give her the love she deserves?

Thank you
RTS

Mate, don't worry about that. Six years ago a friend of mine tried to kiss me at a mutual friend's house party, I backed off and tried not to make a big deal of it. Litterally a few hours later she hooked up with another one of my friends. A few weeks ago they got engaged and I was asked to be the best man at their wedding. I've never seen two people more dedicated to each other - she certainly would never have fallen in love with me, and I wouldn't have fallen for her. I bet she'd be incredibly grateful that she never kissed me, even if she could remember (she drank a hell of a lot that night, and I decided not to furnish her with this information.) No one can ever predict how events might shape the future, life is far too complicated to ascribe one reason for why two people fall for each other, especially a reason as mundane and trivial as "someone else turned her down once". You did not reject her, and apparently you both turned out to be great for each other, a trillion things could have conspired against this eventuality happening - you shouldn't fixate on any of them... It's just the butterfly effect.