Unmarried separation

[adagio4wings]

DP and I have one DC (3 yo) and are not married. We have not been getting along for a while and we are currently receiving relationship counselling.
I have decided to take it upon myself to research my rights, entitlements etc as I'm beginning to think it's not going to work out. I need to know where I stand with everything.
We have a joint mortgage, however the property originally belonged to DP and I moved in with him 5 years ago. He put down a hefty deposit given to him by his parents 2 years previously and we do not have a clause in the mortgage which says X amount should go to DP.
DP pays more money into the mortgage than myself as I have only ever worked part-time. I am worried that I won't be entitled to much should we separate; I also think that he will fight for atleast 50/50 custody based on him having a higher income and more financial rights over the property than myself.
Aside from this, I worry about DPS ability to take care of DC single handedly if he was go gain 50/50 custody. DC has a had a range of health issues from birth, I have nevery had a night away from him, whereas DP has had many. I do not think he is capable of meeting his needs entirely as I believe he is on the spectrum and often misses important cues. Once a paramedic had to shout at DP to help tend to our child after I called an ambulance out to him and DP was trying to make cups of tea.
I have no.idea where I stand, particularly as we are unmarried and I am nervous about shared custody. Can anyone advise?
I'm terrified.

You need to take legal advice on how the value of the house will be split. In what shares do you own it (that will be he starting point). This means what is on the deeds, not what is on the mortgage. If you do nit kniw, you need to find out.

As it was previously solely his house, then it seems sensible that he buys you out of your share. Have you worked out where you will afford to live next.

I doubt that the fact he has occasionally been away (for work?) will make much of a difference in sorting out attangements for your DC. And I doubt an isolated incident when paramedic attended would be a clinching argument on unfitness to parent either.

When you are separating, you need to get your mind round the idea that you will no longer be a daily presence in your DC's life but that they will be with their other parent. And that's OK.

As said above check the ownership. I am a bit confused by your post. The house was in your partner's name but then a mortgage was in yours and his name. That is very unusual. At some stage was the house moved into your joint names and if so why? I think you would have had to pay stamp duty if it were transferred from one name to two so people often won't incur that tax. Anyway check on the land registry £3 on line search first to see exactly what is said - it might eg say you both own the property. Then check if you won as tenants in common or joint tenants - your original solicitor may be able to advise you on that and if joint tenants you probably want to "sever the joint tenancy" so you can leave your share where you like.

Then look at if there were any deed of trust signed when you moved in - this will not be at the land registry but your own records or your solicitor's might show this. It might say eg your ex owns 60% or some other percentage. if it doesn't then probaby you own half each. Was his parent's money a gift from them or a loan ? That obviously makes a big difference.
He will probably be able to buy you out of the property and you won't have enough money to buy him out I am guessing unless you can assert some kind of Children Act right if the child stays with you.

Don't assume he will get no contact.