Hi, I would like to point out that flirting can be harmless and it is possible she doesn’t mean anything by it. Some girls don’t get along with other girls and might be looking for attention where she might be insecure or possible lonely or bored. If your jealousy is not something that concerns her, I would be concerned. She likely will be happy to receive more attention from someone who she has chosen to be in a committed relationship with. Just my two cents... I think the best thing to do is talk to her and decide where you both want the relationship to go. Maybe rekindle early romances or take your relationship to new places. Be careful not to poke too much or spark unnecessary arguments. It is also possible that some people are pushed away by their own insecurities and sometimes people simply grow apart..