Ex is misleading

So me and the father to my daughter have been having casual sex. We broke up because he decided he wasn’t over his ex. I let him be. Now he comes over occasionally. My sister saw him getting in a car with his ex. Today he commented on one of my pics. The other day he asked me what if we got caught up. In all honesty I don’t take him serious I see him just having his cake. I woke los the mother of his other child tried to make my pregnancy miserable by sending me pics of them and doing the most. Advice I thought I’m just cut him of and keep it strictly about our daughter.