The bad/good

So....I think our bad is starting to put weigh the good. I tried so long to make this relationship work. I'm tired of being the only one trying. I'm tired of being disrespected and not being a priority. I'm tired of him flirting with other girls. I just wish I had the strength and courage to just walk away. But it's so hard....I feel like I am trapped. Every time I want to leave he begs me to stay saying that he will change. I just don't know what to do. It especially sucks cause I really have no where else to go... :/