<human>: Before our relationship, I was pretty self secure and I wasn't really affected by other people's comments and their status. 

I'm not very experienced and this is my first relationship, so I've come to /r/relationships for help. I don't know how to build my self esteem back up and I'm not sure I feel comfortable with her flirting with other guys. She's had boyfriends in the past who were comfortable with it and so she hasn't really had to change her behavior and it's unusual to her that I'm bothered by it. I'm not sure what to tell her, what to do, or what I should be thinking.

Can you summarize the given text in a few sentences?
<bot>: My girlfriend flirts with other guys and it's made be self-conscious, and I don't know what to do about it.