<human>: The guy I date is married. 

He and his wife have an open relationship. I've asked a lot of questions about this and it seemed like a stable, healthy, happy situation. 

Today I found out they are getting divorced. They have three children. I was told that the divorce has nothing to do with me, I am  respectful of their rules and relationship. I like that there are clear boundaries and limits in this situation. 

That said, those are about to go away. I care about this guy and want to keep seeing and sleeping with him. But I am not in a place where I am prepared to be his monogamous girlfriend, should he want that. I don't know how to be supportive but maintain good boundaries in our relationship. I do not want to be a stepmother to multiple children. 

I am basically looking for good advice for people involved indirectly in poly divorces.

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: Married boyfriend is dropping the married title. Not sure how the boyfriend title fits now that we're dropping the married part. Open relationships of reddit, help me sail these unknown seas.