I'm kind of waiting for the other shoe to drop.
Yeah, this is what life with an addict is like. You get used to the feeling, so much so that it may fade into the background sometimes. But then the shoe drops, everything comes screaming back, the dust settles, another shoe appears and now you're left in suspense waiting for it to drop again.
I'm so sorry he screamed those things at you. Mine did the same one day when he came home from a business trip and he had a flat tire after I had driven his car. It was before I found out about the affair, but it was definitely in the middle of it. Wouldn't stop calling me while I was at work, and when I wouldn't pick up the phone was texting me in all caps, FUCK YOU! FUCK OFF! and other fun things.
I had seen him angry before over all sorts of stupid shit, but never that angry, and not at me directly. It was really so jarring. I wish I had done more digging at that time instead of accepting his apology. I remember forgiving him because I felt like it was so out of character for him. Please don't do what I did and let him convince you of that. He's showing you who he is, you need to believe him.
Sure, he can be super nice when he wants to be, but that will only last for so long until the next blow up. Also, the fact that he is being nice to you now shows that he can be nice when he wants to be, he just chooses to treat you like shit, cuss you out etc. You don't deserve that.
And yeah, the Jekyll and Hyde thing. I felt that too. Way before we split, years earlier in the relationship, I told him that. That I didn't know who to expect from him, Jekyll or Hyde. We thought he might be bipolar (I didn't understand that diagnosis as well as I do now that my brothers have had manic episodes and been diagnosed). I remember him in a crying fit one night asking me if he should get evaluated for bipolar.
After coming to SI I discovered BPD - Borderline Personality Disorder. It felt far more fitting to describe his personality. And when I sought support forums re: being the loved one of a person with BPD, man did all of their stories ring so true.
I'm not qualified to diagnose him, but the diagnosis doesn't really matter. It helped me to talk with others who had similar issues with their spouses/SOs. Even just to read their own experiences with it. I felt less alone, and certainly less crazy. I had a similar feeling of recognition when I came to SI and started reading our Spouses/Partners of SA thread. Because yeah, it's infidelity, so it fits under that broad umbrella. But it's also so specific, and hard to explain to those who haven't lived it. Here it was like ahhhh, yes. That's it. They get it, that's exactly the thing. They put it into words.
Re: the living situation. I kind of wished I had forced the situation and not spent so much on temporary housing in order to get out. But I also reacted in the moment and on DDay something just snapped, I rented a UHaul and got my family to come help me move things, no questions asked. It all happened so fast I didn't really have a ton of time to think about it. In retrospect, I could have stayed and saved a lot of $$. However he was particularly toxic and said if I came back to the house he would force my step daughters to go stay with him and the mistress at her house, which I wasn't going to do to them, so I didn't really have much of a choice.
I can say with confidence that I'm in a much better place with my mental health than I would have been if I had stayed. Going NC helped a lot with that. I'm in a much shittier position financially though, and that does stress me out, so it's not all sunshine and roses on the leaving end either.
You do what you've got to do. If that means staying in the house until the divorce in order to save $$, so be it. If that means getting the hell out of there so you don't have to deal with him, that's fine too. If the dogs were not an issue, what would you want to do? Use that question to assess how you really feel about the situation, then go about trying to make the dog issue work for you no matter which route you choose.