So she has been on the scene in marriage 1 and now in marriage 2.
He's not going to stop banging her is he? whether you like it or not.
The sex outside the marriage was about her, be honest, and is between the lines of I'm not going to stop banging her, so I'm asking your permission so you share the guilt of it all.
He's only asking now, because he's out of work and therefore all of his movements are accountable. If not for this, he'd be banging her behind your back, whether you like it or not.
From a financial perspective, if he's not working, he can't afford to be spending his money or his energy on anything extra-marital.
She clearly has no respect for herself, or for you and doubtless considers as she pre-dates you, that you are not a threat/deterrent. He seems to concur.
This lack of respect from them both shrieks volumes. His threats to you about fighting you tooth and nail for your son is laughable.
How will HE leave, and raise a son, and a mistress on income support? Or is she loaded?
The court wouldn't remove a child from his mother without bloody good reason. he's using this as a stick to beat you into submission.
He's not contrite, he wants to have this concubine on the side with your blessing, which he's forcing you to give or he'll take your son.
What a prize wanker this guy really is, sorry, but he really is.
Living without this guy will be so much better for you, and for your son. It can't be any worse than living as you are currently.