Leave or not?

So money's tight at the moment, I'm on maternity leave and I've used up my savings as my boyfriend/father of my child is terrible with money and is constantly asking to "borrow" and then never paying back. We split rent and utilities and then I pay for groceries and everything else. Just found out that not only was my boyfriend exchanging dirty messages with a coworker but he also won £4000 and didn't mention it.

Now I'm not saying he should have given me any money but he could have at least paid his half of the grocery bill or like mentioned it at all...

The only reason I know is he let me use his old phone as a camera, he thought he'd cleared everything off it but it kind of backed everything up and there was all these dirty messages and screen shots of him winning the money. I didn't mention the money to him but I confronted him with the sexting and he wants to work on things 🙃