<human>: Can you summarize the given text in a few sentences?

I love my gf, but lately she has been extremely jealous with me. She told me that she feels that every girl that approaches me is a treat to our relationship. I'm not gonna lie. It's kinda cute to see my gf jealous sometime because I can see that she actually cares about me and loves me...or so i though at first.

The past two months she has been acting extremely jealous. She gets pissed sometimes for little things. She later apologizes and tells me that she doesn't know what's wrong with her, that she is afraid of losing me and that fear makes her act completely insane sometimes. She has a lot of insecurities. She had two relationships before me. Both guys cheated on her eventually and she says that the reason she gets so jealous and possessive sometimes is because she is afraid that the same thing is gonna happen with me. 

I try to be patient and assure her that I love her and she has nothing to worry about. The thing is that I now have this idea that she is the one cheating on me. A friend of mine planted this idea. He told me that often when a girl gets jealous a lot is because she cheats a lot. So far I don't have concrete evidence that she is cheating, but now I feel that I'm the one who is becoming insecure.

Does any of you have any advice? Do you think that I should be worried about her cheating on me or not? 

Thank you.
<bot>: Gf gets really jealous of other girls that I speak with which makes consider and that she might have cheated on me in the past. Should I be worried or not?