My partner (35M) and I (30F) argued last night and I’m worried things are ruined

My partner (35M) and I (30F) have been dating the last five months, and we’re very happy together. When we first started, he told me that he’s still friends with his ex (29F) as they share a friend group. Their relationship was five years long and ended two years ago. She’s been in an open relationship with her bf (47M) for the past year. I had no issues with their friendship as long as it was just platonic on both sides.

Since we started dating, she’d been doing uncomfortable and inappropriate stuff towards me and our relationship - cornering me at the bar and trying to be overly friendly, calling my partner multiple times late at night and claiming pocket dials with no voicemail and many retries, telling me how beautiful and perfect soul my partner is in front of both her bf and my partner, used an anonymous instagram to watch my stories, etc. Once this started getting inappropriate, my partner distanced himself and told me to ignore it. I wasn’t satisfied with just ignoring and we have argued about this several times, usually after drinking a lot. He insists that this isn’t his fault, he didn’t ask for this and we’re better than stopping to her level. I wanted her to be put in her place and to leave me alone. He’s talked to her last week to leave me alone, and the next night she confronted me trying to say that she supports our relationship and wants for our happiness. Because of all the drama her actions have caused, I told her I don’t want to engage. She insisted on talking at me. I told my partner who told me he would talk to her again.

Last night we go out for drinks. Our plan was get some drinks then go home and watch a scary movie. Ex shows up with her boyfriend but doesn’t talk to us. Once I go to the bathroom, she talked to my partner, giving him a pack of Pokémon cards and saying happy Halloween. When I come back and am told this, it just set me on one. I was upset that she snuck around and how he’s told her to leave us alone but she won’t. My partner and I started to bicker at the bar; me complaining and him frustrated saying that all we do is talk about this and ruin the night and this is the same old same old. Then we left home for a nightcap. At this point, we both had 3 drinks. We get home and argue more. He suggests that maybe we get some space for the night because he can’t do this. I ask him if I should leave, and start crying. He tells me I can do whatever I want and he’s not telling me to leave. I call my best friend crying and calm a bit. I apologize to him and we have sex.

This morning, we both wake up anxious and he’s spending the morning helping me calm down, holding me and having me breathe with him. We have sex and I ask him if we’re okay. He says we are. We talk about the night, him explaining that she gets in my head and I obsess which soils our plans. He mentions that whenever we argue it’s always after I’ve had too much to drink and I need to take it easier. I’m ashamed and guilty because I’ve apologized for this behavior before then repeated it. I told him I’m upset at myself for doing this again after saying I would change. He insists to not beat myself up but just try to improve this. While talking to me, he’s rubbing my back and consoling me. He walks me to my car and while saying goodbye, he says we’ll hang out and talk tomorrow. I feel so bad that I went home from work early because I was endlessly crying. I’m worried things aren’t okay even though he assured me it is. I’m just looking for someone to tell me if it is okay or if this may be the end.

TLDR: my partner and I often drunkenly argue about his ex girlfriend being inappropriate and upsetting me . We did again last night and I’m worried things are ruined. I’m seeking reassurance.