Missed the bit about the mortgage being in his name
If you are paying for everything I think you might have a claim on the house.
Taken from www.familylawgroup.co.uk/news/what-rights-do-you-have-to-your-home-if-you-separate
If you are co-habiting, it is possible to apply to court to obtain an occupation order, if you satisfy the balance of harm test which, if granted, would allow you to continue to live in the house. This is usually just a temporary measure, but it may give you sufficient time to prove your entitlement to an interest in the house
and also
If you have solely paid all the household bills it could be argued this is above and beyond what is expected of an ordinary cohabitee
I think you need to split up but before you do you need to see a solicitor to see if you have at least a claim on the house or just to get a percentage of what you have paid out over the years.
I would also be looking through every single transaction on your bank account and any credit card statement and working out what was spent on bills, mortgage, home insurance clothing for dc, expenses like nursery fees, school trips etc, food shopping, days out, holidays etc In fact anything where you have spent money that was not just on yourself. List it in categories eg Mortgage payments (if this is a repayment mortgage I would have the payments you made split into interest on the loan and repayments made towards the loan) children’s clothes, holidays etc Plus put down any payments he made to your bank account
Then armed with this information I would see a solicitor
I still stand by what I put in my PP about your fiancé. But whilst a lot of posters are saying to transfer the bills back into his name, I would keep the status quo until you have worked out your legal position
You can get usually a free session with a solicitor so I would go to a few to lay out your issues and to find someone who you feel comfortable with.
Use your anger to keep quiet and keep secret what you are doing
Whilst the law states that if you are only living with someone and you split up, you are not entitled to anything, however in cases like this where you have been paying for everything then other laws are there to protect you