Relationship issue please help!?

SO i been with this girl since 2007 met her with a kid already from a previous marriage she had, we are not married an had a baby with her in 2008, Seems my girlfriend has been jealous around 2008 noticed it around that time, She thinks i look at other women when i don't, i got slapped once at the mall because she thought i looked at another female, she gets jealous im watching a TV show an a girl happens to come on she starts freaking out saying oh looks like you starring at her, what should i do i talked to this girl already about how i feel sometimes we cant go out as a family because she has to stir up something related to women an then she takes the kids at while i stay at home because we are not getting along. Recently i wanted to get myself a mountain bike an we started doing research on a bike to get an when we watched a video of people mountain biking she got all upset because there were females mountain biking what harm was that i couldn't help that a lady was riding a bike in a video.. SO my question is what should i do should i leave her?? i Don't like the situation im in where a girl is always wrongfully accusing me it makes me feel really low an when i get upset an tell her how i feel she starts putting me down in alot of ways an saying how im no good an stuff. I been good to this girl since day one an it seems its all about jealousy, SO what am i suppose to do as a dad?? we are both 26 of age i feel as if i choice the wrong girl