This is what I think will happen .
He will find a house that he wants to buy. He will use his money and your savings for the deposit and pay for the transaction costs . He will tell you that the mortgage advisor / lawyer says that it has to be bought in his name only as he earns more / has a more stable job and you are not married.
If you object, he will say he was going to propose but he won't now as you are being so difficult and not appreciating everything he has done for you . That he had been planning a romantic proposal but you have spoiled it .
So you will comply . After some time in the new house you will ask him again and eventually he will spend £500 of your deposit on a ring for you .
Once you are engaged , and he will say that you can't set a date for the wedding yet as you need the money to buy things for this house . That you are money grabbing as he's no sooner bought you a beautiful ring and now you are nagging him to pay for an exensive wedding. After everything he has done for you.
You will continue to live together and he will pay the mortgage and the bills. You will pay for food, your car, per total and everything for the children .
As long as you go on doing his housework, his share of the childcare and paying for and cooking his food, he will be happy . When you stop doing as you are told or complain too much about big being out all weekend and every night , he will dump you .
He will own the house , you will have nothing . His career will be doing well, yours will be affected because you have taken all the time off for the kids and gone part time.
You will be the evil money grabbing ex who wants him to pay for his kids . So he will quit his job and go self employed . He will pay you practically nothing for the kids and you won't be able to prove his earnings .