How do I F43 get off this sinking ship with M50

So hi folks I’m new here and I don’t know if I need advice!! My apologies in advance for the long rant! So me 43F met an amazing guy (on paper) 50M on a dating app during covid… looking back there were so many red flags but I chose not to do anything because I’m an idiot… so anyway!! First date we do the covid thing met for a walk in the evening because we both work I have a coffee he has a pint or 2, I put it down to nerves, things go great! He’s successful own business own house, divorced no kids… me works in finance own house older teenage children never married. We get on great like the same things laugh seems sweet. As the time goes on we get close I spend Saturday nights in his, but I noticed quickly enough this guy has a drinking problem… still ignored the red flags!! I put it down to maybe he just can’t handle his drink and it’s only weekends, but he would drink so much that if drank on a Saturday night the Sunday was a write off…. Meet the family for drinks the brother instantly tells me my new guy is an alcoholic!! Now I’m thinking if you know this why the f**k don’t you step in to help him out (turns out he keeps them afloat, so him in rehab not working doesn’t suit their lifestyle) I say nothing but keep it in the forefront of my mind! Roll on a couple of years, we’ve had our issues …. I no longer stay in his because I’m not giving up a weekend to watch him hungover and when he stays with me I’ve a strict no drinking policy in my house on a work night and an absolute no spirits in my house at all!! Things go well we fall into a little routine….here lies the problem the last couple of months or maybe even a year he has just become a nasty sneaky drunk…. When he’s not with me he calls me and gets abusive!! Says some seriously nasty stuff and come the Monday he’s all apologetic, but when he’s sober he’s great, can’t say enough about how good he is but I personally feel like a babysitter to him at this stage, if there’s a family event I’m expected to go and keep him reined in (which I haven’t done in a year, he’s their problem they had years to step in) …. At this stage I just want out but can’t seem to cut myself loose! We broke up about 2 weeks ago and this passed weekend was just the worst I did block him, but then I worry and unblock him, but I refused this weekend and made the mistake of reaching out to his friend/neighbour to check on him…. Now here’s where it gets f**ked up

This neighbour 50M single and straight has been a childhood friend of my partners. When we first got together neighbour lived abroad and when he came home to visit family stayed with my partner and it just seemed to be a party weekend for both, I never stayed at the same time it’s not my thing so I only really knew him in passing found him polite but I was wary, only associated him with my partners drinking. Anyway about 2 years ago neighbour comes home for good moves into family home next door and all is well. He’s home and working so not on holiday mode. We’ve been to a couple of events together and have had a laugh.

So this weekend he reaches out to let me know my partner is drunk but in one piece I say fine thanks for the update and fill him in a little on what’s gone on. He’s fully aware as he’s seen him home every night the last couple of weeks so knew there was an issue with us! He then tells me he’s spoken with my partner previously about the way he speaks to me as my partner likes to take all is calls in the garden (mortified) and he has heard him talking to me like I’m a piece of sh*t. We text on and off about my partner. As the days progressed over the weekend he continued to text and check on me. He has sent me the sweetest and most compassionate voice notes I’ve heard in along time and I instantly think, there is no way my partner could ever be this nice and thoughtful and this is exactly how I dreamed of being treated. He has told me to just cut him loose if even for a month to hopefully kick himself into shape!! Now today my partner is all apologetic again saying he’s going to go to AA all stuff I’ve heard before, but I do love the sober parts of him but I don’t know if it’s just a habit of now of breaking up and making up that I need to just cut the cord altogether.

My query well two query’s actually or maybe more, I’ve never given the neighbour a second thought but now I can’t stop thinking about him! Was he just being super sweet because of the situation or do you think he could actually feel something towards me?
Do I give my partner a chance to make this better or do I wait to see if he does do anything about his behaviour and then review the relationship or is it just toxic and I should cut the cords now?

I don’t think I’d ever go there with the neighbour anyway due to the history they have, but if I was to get back with my partner could I hide the feelings I currently have for the neighbour if we are all together.

I hope that makes sense and somebody could either give me some advice or help me give my head a wobble.