"Bad Day" vs "Bad Life"?

I want clarity. I used to live with my husband, now ex, who every day had a “bad day.” I loved him, but did not want to live with him anymore. I chose divorce (2010) after 14/15 years of marriage.
But now I have a child who is nearly the same as my former husband. “Child”… he is 21 now.
I do not want to choose to “divorce” from my son, maybe.
I love my son, but I don’t want to live with him anymore.
I feel guilty and I feel like “if I can’t figure out how to not be upset by his constant moodiness/anger explosions, etc., I’m doomed to be alone forever cuz I’ll just “divorce” everyone!”
Now I KNOW that’s not true because I have some other kids I LOVE living with who are about 50/50, but I still tell myself I’m doomed to be a hermit if I don’t figure out how to not be triggered by my son’s constant emotional triggers (his whole life).
If life is about 50/50, that feels do-able… but living with someone who experiences life as maybe as much as 5% good/95% or more bad… yowza…
We have had our son in therapy, but I can’t help but wonder if he is just “supposed to” experience life as “awful” and maybe it’s ok if I don’t want to experience life the same way or in the same house?
I just feel so guilty for not wanting to ride this ride with him anymore… like I’m giving up on him.
I’m like Brooke in her past… not wanting my child to suffer, but that’s almost all he does.
I almost want to be able to LOVE that he is suffering because maybe I can make that mean he’s having one hell-of-a life experience! Holy Shit!
Will you please help me find thoughts that allow space for his experience of life without me wanting to run for the hills?
Is that possible?
Is is possible for me to be an awesome, loving, compassionate mom that also does not live with her adult son?
When I’m having an awesome day, and he explodes, is it possible for me to remain steady in my mood? Or is this when choosing to feel upset by him being upset could serve us and our relationship?
I do not want to coach him, but I wish someone else would so that he could be happy which makes me think I could be happy (insert cringe-face emoji here)
I know cognitively that my happiness is totally up to me creating thoughts that generate happiness.
But omg! Please advise me. Thank you.