He's a grown man. He supported himself long before I met him. Why do I need give him my house just because we shacked up together.
Why should he pay your mortgage, utilities and bills just because you shacked up together? Nobody is saying you have to give him a house but if you want to be a family unit and expect him to contribute then he should be given a financial stake to ensure his own financial security.
Taking the actual mortgage out of the equation he's still not paying even half the bills.
Why should he pay half of the bills?! There are 5 people in the house - he already pays 1/3 of the bills, which subsidises your children.
My children's father passed away. I'm not sure he would have liked me giving away half his house.
Then why "shack up" with a guy, move him in and have his baby if you have no intention of allowing him to have any stake in the property ou want him to contribute towards?
The DC are teenagers he doesn't need to parent them and isn't doing any childcare.
But you want him to pay for them. He pays 1/3 of the bills despite being 1/6 of the household. The budget for food/utilities especially if they're allergic to turning off lights and having 30 minute showers like my DD etc for 4 teenagers, will be more than 1/3 of your montly expenditure. Do they contribute to the bills? Your children are your responsibility, not his.
I live with DD12 in NW England, so a definitely a cheap area, but my essential bills - rent, council tax, water, electric, gas, phone, internet, insurance, travel, groceries - come in at just under £800pm for my 2 bed flat. It is a Housing Association flat (though I pay average market rent for the area) so it is a secured lifetime tenancy, and I will have an option to apply to buy it after a certain number of years. Your partner might be better off getting his own 1/2 bed place and being only responsible for himself and his one child than having to be responsible for funding your 4 children yet having zero financial security.