Baby mama drama

Ladies I need help how do you deal with your man baby mama?

My man bm doesn't know about me but I know about her. He's afraid that if she knows about me then he won't be able to see his son.

But I can't help but get jealous and feel like I'm missing a part of his life and feel so outside that I don't even fit into the lifestyle.

I know he's with me and loyal to me but I just can't stop worrying about they day he will drop me and go back to her. He told a close friend that if the time comes and his bm say "baby come back" or "I want you back" that he will drop me in a heartbeat and complete his family?

Am I wrong for feeling the way I do? And how do I handle this situation?