Can babymamas be side chicks? Read below, saw this online

Me and baby daddy were together for 2 1/2 years. I left him because he was cheating on me. We have a 10 month old son. He lives with me but BD gets him every other weekend. I don't have him on child support and I'm not planning on it. So anyways me and BD still have sex mostly when he comes over to pick up or drop off our son. I don't have romantic feelings for him but our sex is great plus I'm comfortable with him. He's the only guy I'm sleeping with.

The thing is BD has this gf who thinks that I'm just going to magically disappear. She hates me. She hates our bond. She wants us to be those co parents who hate each other and it's not happening.

Anyways she found out something was up because me and BD were exchanging pics and I guess she saw them *shrugs*. She went off on a tangent calling me "baby mama and side chick" saying she's gonna "beat my ass." (classy right). sigh.

So back to the original point I'm not a side chick, I'm the mother of his son and I'll be around for 18 years and there's nothing she can do about it. He initiates the sex every time. What can I say?

I also want to add I don't support mistresses and homewreckers but she's not his wife. She's just some girl he'll be with for a few months, maybe a year and he'll move on. I know this guy better than anyone, he's a good guy at heart but dude has some serious commitment issues.