I had to try-read this article to check I’d not mis-read it; so MANY huge red flags. His behaviour sounds appalling. You should not be this unhappy. Your situation has to change. Some suggestions to start off with:
1) Insist on transparency of finances. It’s audacious that he borrows money and yet doesn’t explain his spending.
2) STOP LENDING HIM MONEY and start saving your own for a get-out fund. You may have to leave if things don’t change so please start planning.
3) explain to him that his behaviour is becoming a deal-breaker and you’re miserable. It sounds like even if he does care for you he knows you’ll never say no so he can be complacent. It’s hard I know but try not ‘enable’ him. He grows up or moves out. You shouldn’t have to be his manager but needs must so set a specific task list of jobs/duties that are easy,hard to forget and AFFECT him too if they’re not done: eg things like emptying bins, 20 mins of tidying stuff he uses, hanging up laundry (otherwise don’t wash his clothes, he’ll soon notice when he has no clean pants) And eg: you get a 2 hour lie-in once a weekend where he takes baby out in the pram. He should be able to do that. If he can’t then….oh dear, please leave him?!
4) if you can afford a cleaner for a few hours a week get one. HE can pay given he earns more – suggest this to him as one way of him upping his contribution to the chores.
5) please stop organising his appointments. If he screws up it might teach him to get sorted.
6) maintain/build up a good support network around you for emotional support and also as a back up for when/if you leave your partner.