Road trip and arguing

We will be in a minivan conversion van for the next 3 weeks together traveling. Last week in the first few days of our trip I brought up the AP. I must mention the cheating happened about 6 years ago. I found out a year later. Chose to stay and he shut down any conversation about it. I have not been able to move on.
I broke up with him over something else and this combined last summer. We tried therapy but my schedule has not allowed me to be consistent in anything for a little while.
So we both had been hiding our feelings and not talking about things. It got better after therapy. We try to be more open emotionally.
I briefly mentioned her the other day. We were discussing a time where we thought he would have to move away from me and I was upset. I then said it was immediately after finding out about her as well so it hurt more.
He was very upset that I brought it up. Said he “always gets the bad end of the stick”.
I think about it everyday. He seems to carry NO guilt but he has the bad end of the stick? Seriously. I’m stuck with him in the minivan for the next few weeks but very much feeling mentally done with all of this. I have came and gone from this sub so many times thinking I’m okay but it’s never gonna be okay. I truly feel like he has blamed me for all of this and has no problem making me feel bad about it all. I cannot open up to him about it without feeling shamed for being sad. I guess it’s just how he copes or deals with a conscious if he has one but Idk anyone else experienced their partner being like this and still continuing R?