Husband always aggravated & angry

Wondering what solutions any of you have. I have been married for almost 18 years and I am so tired of being 'in trouble' with my ADHD husband. Every time he gets aggravated, annoyed, frustrated he blames whoever could be responsible and it is usually me, and often our kids. We have several children from teens to preschooler.

He had has anger issues his whole life - his dad did too and it is the reason he is twice divorced. His parents got divorced while he was in high school.  Between his very emotional ADHD and the wounds from his upbringing I am completely spent dealing with him. I have recently been asking him to try Celexa after researching that is the next step in treatment after stimulant meds, which he does take after years of resisting, and he initially said absolutely not. I have told him that I take SSRI's just to reduce anything I do that sets him off and that it is not fair that I take them for him and he won't for me, so maybe I'll stop. But why not try them for a month and see if we fight less, if he feels happier? He said his appointment is in May.
But until then, we are on a family vacation, and every day he gets exasperated about some mistake I make. I forgot where our car was in the parking lot for 5 minutes and he was beyond irritated and let me know. I booked lunch reservations and he didn't want to stop our time in an amusement park and complained for the hour leading up to it, while we ate, and the hour after. The problem is all this walking on egg shells impact how I am to my kids. They don't always see the ways he chastises me. Worse though are the times they do. My older kids now speak openly about how he is being such a loser about stuff and can't let anything go. He feels his responses are perfectly reasonable and the problem is with me. 
I woke up today knowing I am going to do something 'wrong' today and it is just a waiting game until I do it. Everything has to be his way and there is no 'laid back' approach to life ever. I walk on egg shells all the time. I read on these forums that people who have set up coping mechanisms for their adhd can't handle when anything is out of their control and that sums it up pretty well. It has massively impacted my life, sense of self to live like this. I am trying to do healing work with my therapist and read every book I can get my hands on, but I am at my wits end. How to you put up a boundary with this type of behavior? And how to I ignore him getting mad at me so I stay positive for my kids? Thank you.