It sounds like your H has gone through something huge - even traumatic. And that he is panicking. Reuniting with his birth mother is bound to have an absolutely huge impact on his life - most people would want therapy to navigate this kind of thing. It is totally understandable that it would make you feel insecure, and, I think, understandable that he'd panic if he felt like he needed to choose. Especially if, in his mind, he'd nearly always put you first, started to resent it, then decided that his bond with his mother would be the final and most important thing he wouldn't capitulate on.
I think the only thing you can do is give him loads and time and space. And get rid of the cameras in your house so you can have time and space and privacy too.
