Need serious relationship advice!!

Hey ladies!

I really need some help...

I’ve been with my fiancé for nearly 3 years! We got engaged last Christmas! But I’m going to explain what’s happened during our relationship and I need to know I’m not being stupid about things.

When we got together she had just got out a pretty crap relationship and I feel she rushed getting with me once I found out how soon it actually was (a couple of weeks) but I thought I’ll see how it works out! So after a week in come the messages from her ex, I explained to her I don’t want to be involved in their business as it’s nothing to do with me so please leave me out of it! Which she did for a while but she would phone my partner CONSTANTLY and all night long and when that didn’t work the messages started again and it got crazy we got to the point after 6 months we were going to file for harassment 😫 but once the police got mentioned it stopped! So not your average honeymoon period to a new relationship and already I was starting to feel hurt my partner pandered to it for so long and let this other woman abuse me so much when I’m a total stranger to her!

So things started going well after that, for a few months until my partner started messaging her other ex girlfriend no biggie I was okay with it! She seemed nice and friendly and I was good friends with another ex partner of hers so why not this one too? So I went out drinking with them and tried my hardest but I could tell this girl wasn’t interested in being friends or even wanted to talk to me - people clash that’s fine! However she then started getting flirty and posting old relationship photos of them and I love yous, then the messages started to be deleted and things got weird my partner would go out and not come home till the morning or start arguments out of thin air and disappear... this carries on for months until last Christmas i met up with old Work friends and they told me they saw her a couple times with another woman yay her ex... so I confronted her she told me I was fucked up and crazy so I messaged the ex she told me “everything” they had been meeting up regularly in secret and having long phone calls and erugh it broke my heart. Our relationship was on the rocks and out of no where she proposed and I panicked and said yes if she could try work with me and overcome or problems! Great, well the last year her drinking got so bad... awful, she’s officially an alcoholic, which explains past behaviour of starting arguments for excuses to go get pissed up however when she’s drunk she’s nasty, so much abuse comes out of her but it’s the “I don’t remember” in the morning so one night she started on our friend and she recorded the whole thing and it finally gave her the shock she needed and she gave up drink we got through the withdrawals I stayed by her and looked after her well that lasted 2weeks and now I just.... what am I even doing :/ when it’s good it’s great but I’m so broken down after it all... do I really want to marry this girl? 😫