Help needed to solve property and mortgage during the separation!!!

iandson

Hi all! I and my husband (still) are married for over 8 years and bought our first house 7 years ago. We have a 4 years old son. The deposit for the first house was paid by me from selling the property I owed abroad before the marriage and I have paid every single mortgage payment since! My husband started to drink heavily over the last 3 years (main reason for separating/divorcing) and does not contribute towards the household much (300/month)... I want him to leave and offered to buy him out, but he refuses (who wouldn't-he has it too well: son is looked after, wife earns good money and pays for everything!)... He wants half of the house and wants me to sell... I know that if I remortgage the house on my own name only, I would be able to afford to keep the house and pay him off just under the half of the equity (short about 5k); however i will struggle to keep up with the current mortgage payments (£1400/month; I know- it is high-but it is due to his age - we had to have a short term mortgage) if he does not allow me to take his name off the deeds and accepts the offer...
SO.... Could anyone advice on what I am entitled to ( is he really entitled to half even if I paid (and can prove it) for everything? P.S. I will be main carer for our son. PLEASE advice and HELP- what could/should I do?
I am scared to start the process until I know what I can expect, but I am so desperate to have a “normal” life with my son, so he does not need to see his dad drunk every night!!!