I flirt with people to feel better about myself, but I'm in a serious relationship with a man I love.

20f here, with an exceptional 20m as my SO. I know that we're young, but we have an incredibly healthy relationship and we're both looking forward to the future together.

I have a bit of a problem. I flirt. I'm not a serial flirt or anything, and I don't even flirt because I want something to come of the exchanges, but I do it simply to feel better about myself.

Now, I wouldn't even say that I have low confidence or poor self-esteem. I'm very comfortable with myself. (I do have my days, though. Who doesn't?) But if that's the case, then why do I do this? I end up feeling miserable about it, too, because I love my partner and I love our relationship. He says that he's fine with the flirting, but clearly I'm not if I end up with knots in my stomach.

Can someone please tell me why I do this, and what I can do to stop?