Unable to leave my partner. Please help

need advice on what to do. I broke up with partner over some long standing differences and the fact I don't think we're right for marriage. It was almost 4 years long. I'm a very bad person I get it. After 4 days of no contact she called and asked to pick up its urgent. After an hour or arguing we decided to start talking and fix things again. After ending the call I am just angry with myself. When they start talking I just melt and become a yes man. I love them and it hurts to see them hurt