Other Woman. What now?

Krista
I struggle with jealousy and trust issues resulting from an abusive childhood. My man knows this. I told him when we met. Yet about once a year I find out about him hiding a relationship with a woman from me. Its always been just talking, but he still hides it. I feel like it should be onvious that hiding things from someone like me is the worst possible course of action. Well recently I found out he's hiding a relationship with a woman from work. I read their messages and she's calling him punkin and love and "baby daddy." He's sending her love eyes emojis and saying he likes cideos with her in it cause he can see her. I confronted her and she says I have nothing to worry about with her. I confronted him and he is extremely offended when I suggest he lied about anything. He claims that hiding things from me is how he avoids problems. I feel like it only creates bigger ones. I don't trust this girl and she has been talking to me a lot, claims to know the members of Fifth Harmony personally. Claims to have a record deal in the works as a result of them contacting her after she posted a video of herself singing. But the companies she claims are scouting her are not the companies that are affiliated with Fifth Harmony. So I feel like she maybe lies a lot. And she's still messaging my husband. No more nicknames as far as I know. But i just can't shake my bad feeling. I can't start feelingg comfortable again. He has been discovered hiding a female friend from me about once a year since we met, and I am still not over this one. What do I do now? Now that he has sworn to love only me, and that she's just a friend. Now that he has apologized for making me feel as if he was trying to hide her... now that I know she's probably a big liar... Idk how to feel secure in this relationship anymore. We have three children together. I feel like it is an inevitability that he will just keep right on hiding things from me i stead of being honest and open. We aren't technically in an argument about this girl anymore. But I still am not yet in a place where I feel I can trust him or her. Someone please help.