Kasiodo,
Welcome to the forum, an excellent place to vent and if you will listen, get some really good advice.
Unlike the advice that you might get from professional counselors, most of the advice offered here was discovered the hard way -- first hand at great physical, emotional and financial cost.
I will not offer any direct advice, but I will share part of my daughter's recovery story and let you draw your own conclusions as to your situation which is even more complex since there is a child involved.
"Once upon a time there were two recovering heroin addicts".......K (my daughter) who had been clean for about 23 months and N (male) who had been clean for almost 3 years. They had met each other at NA meetings and both suddenly found themselves in need of finding a new place to live. With the blessing of both of their NA sponsors they moved into a 2 bedroom apartment and maintained a platonic relationship as room mates.
Everything was good for a while and eventually they became boyfriend / girlfriend. Then N was injured; need surgery and was prescribed opiate pills as pain killers (how stupid can the medical professionals be?). N quickly relapsed and K followed him.
N was a very different person when he was using - consistently verbally abusive and very occasionally, physically abusive. Sounding at all familiar?
"The past 3 months he has been clean have been great, but today it's like nothing has changed."
K stuck with him, thinking she could "cure" him. Sponsors, counselors, friends, parents, everyone told her to get out NOW.
After about 6 months of this BS, K and N both decided they would go to rehab and see what happened afterwards. They stored K's furnishings and what little N had in a storage unit and went to separate rehabs; supposedly N and K alternated paying the monthly rent, but K ended up paying much more frequently.
N&K got out of rehab and agreed not to see each other for a while while they worked on their recoveries. They stayed in touch via text and phone. K had moved to a different town for rehab, N stayed in their original town.
They had a chance meeting in the parking lot of the courthouse (it's complicated and way too involved to repeat here); N boasted to K that he had a new girlfriend and that he was done with her. This hurt K, but foolishly she did not give up.
Some time later N relapsed (again) and started texting K with the usual lines of addict BS -- K fell for it . They "got back together" just long enough for him to "share" his STD. K discovered the STD and informed him that he was infected - he was the only sexual partner she had had in months, so it was pretty clear where the STD came from. Instead of quietly getting treated, N decided he should spread the word around town to the NA community that K had given him an STD -- this was not surprising behavior when N was actively using. This upsets K again, but she will not give up on him -- she knows she can save him from himself if she just hangs in there.
She goes to very limited contact and is doing a good job on her recovery and on generally ignoring N who continues in active addiction.
One day the phone rings, it is the lady who runs the storage facility where K's furniture is stored while she is living in a halfway house in a different town. The lady told K that N had been there and had taken "a lot of stuff" out of the unit. She suspected that he was stealing her possessions, but could not do anything since N's name was also on the contract.
K drove to the unit and checked it out -- N left one box of dishes, some of her clothes and her mattress -- everything else was gone - TV, bedroom furniture, tables, lamps, all the kitchen stuff. She is back at zero when she moves out of the halfway.
K finally saw the light and has sworn off N for good (we hope).
So, the question for you is just how many chances do you want to hand out? How many times do you need to be hurt? Sounds like he already has several strikes against him -- how many more are you willing to allow?
You need to do whatever is best for you and your child.
Keep coming back,
Jim