Is it only because he's Jealous?

My bf and I made up. However he said something that made me think he was testing me but I of course ped the test. My ex whom I have a child with was back in the pic after Idk how many months. Anyways I guess my bf tought I was messing around with him or something but I wasn't. I don't love my ex anymore. I told my bf that I love him. Anyways my bf told me that if I'm ever with my ex that it's ok with him because he's the father of my child and that way I can get the financial help that I need and so forth. I said no I'm not like that and that I care about him more than my ex. My bf now calls me like 5 times on my days off. Oh and on Sunday he left me a message apologizing for being mean to me sometimes and thanking me for me being nice to him. He said he's going to change and that things should get better. Should I believe him? I feel that he has lots of insecurities but I'm gonna try to make him feel more secure. What do you think of all this dilemma?