My personal view is that he is playing a power game. Which is immature and dickish between two adults but a disgrace for a father to do it with a child in the middle.
I think he is relying on you feeling financially vulnerable and telling him he must come back because of his earnings. This will be his cue to tell you that his contribution is the most important and you should be doing all the housework and childcare.
I would call him out on this. But I would do it in a powerful way. At the moment you can claim CMS from him so do it. I don’t know how UC would work if you have student income but if you can claim then do claim.
As others have pointed out you have a child and have been married a fair few years. Anything you both own is a joint marital asset. That’s equity, savings, pensions and investments but don’t forget debt. A divorce will split these assets up according to need.
Your need is greater than his because you decided as a couple that you should work PT and study. You will get a bigger share of assets. But you may also be able to secure other consideration which include
- deferring the sale of the house until you can afford to house yourself and your child. Generally you would be expected to pay the mortgage but sometimes in extreme circumstances he is directed to pay it. Given he has a middling income I would be dubious about him being directed to pay the mortgage.
- Spousal maintenance, this would probably be timelimited. It’s generally not used because it impacts on UC entitlement which is a better option for many woman. Again depending on how you are supported as a student, UC may or may not be available.
As he has left the family home you can claim benefits and CMS. Put in the claim for CMS. It could be c£400+ per month.
What you have to remember in this power play is that he hasn’t considered the financial impact. Eventually he will want a place of his own and will need to pay rent on top of CMS.
The paying of the mortgage is one where the biggest bluffer wins. Tell him he will have to pay it as you can’t afford it. Tell you aren’t bothered about getting another mortgage because you can’t afford one and will be renting.