Signing over the house can be a red herring of an asset, depends on the equity. He might even have signed over negativity equity! The devil is in the detail.
As above, he's kept his pension so I'll reserve judgment on the house without facts and figures.
Staying on the mortgage is pretty common, courts issue Mesher Orders for that reason. Even if she worked full time, could she get approval card for the mortgage on her children's home, alone? Or did she screw up her earning potential protecting his?
Life insurance? Meh. My XH pays for our joint life insurance at my suggestion. (1) it was cheaper for him than starting a new policy just on his own life and (2) he's the bloody beneficiary! As I say - the devil is in the detail!
Even the private health insurance - is it a family policy? So it's for the kids. Or... even though they're now teens, has she been primary carer for at least the last 4 years and he thought that giving her access to fast health care was actually in all their interests? If she needs an operation, how much better for him if she can choose a date to suit his children and him, instead of him taking parental leave to care for the children whilst she accepts whatever inconvenient date the NHS can offer?
You are strangely reticent on how you ended up accepting this situation in the first place. And also on what he's contributing to your household.
He can't be that low an earner if he's got another mortgage with you, despite being on his original mortgage.
On the face of it £1100 sounds a lot. But I have an inkling there's more to this... and I expect it puts him in a bad light and not her.
I'm interested in how he's managed to sign the house over to her in a private arrangement. It's not his to sign - the mortgage company have a BIG interest. If he fails to pay the mortgage, they need to come after him for his assets. So they wouldn't just allow him to give the house to her. Otherwise, anyone about to go bankrupt would just give their house to a mate.
I don't think you know everything there is to know about this private arrangement. A verbal agreement that the house is hers won't hold a lot of water. In those circumstances, I'd want the £1100 too, because I might not be getting a lot else.
You also haven't said whether the £1100 includes the mortgage payment.
If CMS is £500, £600 isn't an unusual amount for a mortgage - and it wouldn't be unusual for a court to tell him to pay it.
I'll say it again - stop bitching about the ex and look to your husband with your issues.