Hi op, why don't you write down what you would like to say to him, then put it away in a drawer, each time you want to express something to him do that. Writing helped me get some of the anger out.
Because youv'e not had chance for any closure, with him abruptly leaving this time and this time knowing the reason, you are going to feel like you want to confront him, but nothing will get through to him at the moment. I fear it would upset you further.
I think he would use any conversations with you to blame you, so you don't want to give him the oppotunity to hurt you further.
I think the mindset of him having a wonderful time needs to be changed, he's not having a wonderful time, nobody does, life's boring and mudane, that doesn't change when you up sticks and move on, the daily crap will be becoming the norm for them, add on top his health and guilt, not to mention him looking a complete arse when lockdown eases and he has to face society again.
He hasn't got it good, but even if he starts to regret his decision he will probably have to put the I'm ok face on.
Give it more time, it's so early in your recovery, you will grow stronger.
x