throwaway account for obv reasons. Sorry it this is long but I'm trying to explain everything so you have the complete picture. And sorry for the English, it's my third language

So I (27F) have been together with X(38M) for a little over 2.5 years. I'm divorced with two kids (Matt, 8M, and Lucy, 6F). The relationship with their dad has always been rocky, especially during the divorce (he even tried to take the kids from me for no real reason, apart from knowing it would be the only thing that could really hurt me); but rn we have come to the point where we talk about kids' stuff in a mature way, and we agree on putting their well-being first.

The kids have a really strong bond with X, he's been great to them especially since Matt has had behavioural issues in the past and X has helped me with discipline etc.

The issue is that in more occasions X comes across as aggressive for the way he talks. He tends to yell and speaks as someone who is constantly annoyed even by silly things. I know its not easy living with two kids who aren't yours, and I've often talked about it with him.

In several occasions we've had very heated arguments in front of the kids, which is totally wrong. He doesn't know when to stop, and yells at a point where I can't even hear what I'm saying. I also tend to react in a strong way, or sometimes tears just come out of my eyes, and I can't make anything about it.

Yesterday he came back after 5 days of "vacation" with his buddy, where he stayed at a casino and slept very little: so of course his fuse was already short. He wanted attention all for himself, while I was in a hurry to pick the kids up from school and drive them to their activities. This seemed to really hurt him, he felt like I didn't love him. But as I explained, I had mom duties and I would come back later. I even asked him what he wanted for dinner, and tried to make things nice. But I also told him I felt a bit annoyed too, bc he knew I was in a hurry and instead of coming directly home to spend more time together before I had to pick the kids up, he went to a betting place to collect some money he won.

This angered him even more, as he said I was just being petty and polemic, when my intention was just to express my feelings.

In the meantime he sent me more messages saying the the whole house was a mess, only bc we had a wall repainted and the next morning the workers had to come again, and I left a bit of dust they made. Mind you, I was alone with the kids and a very needy dog and on Friday, Saturday and Tuesday morning I had to work. I cleaned the WHOLE house except from that single spot.

When I came home I helped my kids shower while cooking dinner (the one HE chose), and he was trying to touch me all the time. I said : "let me finish with the kids, so that when they're in their bed we can snuggle a bit". His response: "ahh, the kids always come first, even when I just came home". Okay, understandable maybe, but I'm trying to cook while getting them ready for bed.. the sooner they're in bed, the sooner we have "alone time".

At dinner my kids were visibly tired, Lucy especially, and Matt was a bit upset bc X was taking to him in his "annoyed" voice in a rude way. I told him THREE times calmly to talk in a nicer way. Then he made a joke to Lucy, who is very sensitive (and he knows she doesn't like jokes, as it's not the first time this happened): he pretended to pick his nose and put whatever was inside on Lucys cheek. She started crying hysterically and as I picked her up I said to X: "what kind of stupid jokes are you doing? You know she hates this kind of things". He slammed his fist on the table and yelled, his eyes out on stalks:" I'm fucking fed up with you!"

Matt was as shocked as I was, and started to say repeatedly : "you're an ass!". Before I could even scold him for this, X started to yell again, his face close to Matts. I can't even remember the exact words but it was a really unnecessary and horrible scene.

At that point, knowing that X in precedent occasions hadn't been able to calm down and that I was about to react yelling or crying (I know, I'm in the wrong too), I said calmly to the kids to call their dad and have him pick them up. They were gone in 20 minutes. I told my ex that the kids were just being kids, they had a fid bc of a stupid joke they didn't understand. So I didn't humiliate X or told my ex I was mad at him.

X has broken up with me bc of this. He says I was disrespectful in his regards, and that I shouldn't have called my ex. I was just trying to protect the kids from an evening of yelling and screaming. I don't have any family here, otherwise I would have brought them to them obv.

He insulted me saying I should go back with my ex, that I'm a stupid bitch, that I don't know his rage and now he will make everything in his capabilities to ruin my life.

I know I can be "heavy" and take things too seriously sometimes, but am I the AH? How should I proceed?

UPDATE After reading all the comments saying I’m the asshole and assuming the worst out of this situation, I just wanted to clarify some things. First of all, my kids were always safe and there is no violence involved. They love X, to the point Matt even dedicated the craft he made at school for Father’s Day to him.

Secondly, X has helped us out tremendously in these past years, taking care of us. So I know it’s easy to assume everything is a mess from a single post, but I’ve always had my kids well-being in mind. They found a whole family with X, including several members of his family.

My ex wanted sole custody BEFORE X, and as I said it was just to threaten me into leaving him money and house. Which I did.

Tonight I’m gonna have a conversation with X. I already talked with the kids, they say they love X and want him to be involved in their lives.