Feeling/accepting the pain vs resisting/working past it.

I’ve been in an 18 month extramarital relationship. We were super in love and I was on a plan to leave my (not so great) marriage for this guy. Together, he and I have a business, which I have $$ invested in. He has travelled a lot for the business. At present he is stranded out of the country, won’t be back for at least 2 weeks and then has to quarantine. He left in Feb intending to be gone 3 weeks.
When he left, I was happy, in love, and felt loved. Everything has changed.
In March I learned he’s been cheating on me in a big way. Living with someone when he is out of the country. And a bunch of other really big lies. He really is not the person I thought. It has been a very very painful betrayal, deception and loss. Made more difficult by distance and lack of good communication.
After a nasty confrontation, he told me he loved/loves me, intended to marry me and “change” his habits with women, completely failed, and it was not my fault.
He suggested we wait and discuss everything face to face, coming home soon. Said he’d answer any questions I had. I agreed. Well “soon” kept getting pushed off because… no flights.
Communications were tense, awkward. Finally 10 days ago, via text, we ended it in a nasty way. I knew it had to end, but of course I still have feelings for this person, want to see him safely home and would have preferred the closure of a ftf conversation.
It has been 1.5 months since these revelations and the shocking loss. It’s like the person I loved and was planning a future with died, or never existed. There is a deep grief.
At this point I want to stop feeling and allowing the pain, because I need to get on with my life and my business. Although right now he and I have zero communication, I cannot disconnect from him 100% as he owes me a lot of $$ (the business, which he is running). He intends to repay me, but given the current state of the world, may not be able to. But as a couple, we are done.
I’m a coach. I’ve modelled and modelled and modelled the many various aspects of this. I’m struggling with finding a place in between experiencing my feelings (which, if I allow them, tend to leave me upset even crying, still, and then very unproductive in my life, especially now in this strange new world) vs. “white knuckling” my thoughts to create whatever neutral or positive spin on this situation I can, so I can function.

Thoughts like “it’s for the best” or “thank God I found out before I upended my family for this guy” are true but not helpful. “I had 18 months of happiness” is also true, and sometimes that brings a feeling of gratitude for this experience. (It is interesting as a scholar to notice that even though he was unfaithful for several months, I was clueless and I was super happy! Not because he was faithful. But because of my thoughts about our relationship.) Perhaps the most helpful models go something like this:
C: Lies, cheating, bad breakup
T: It’s painful, part of the negative 50% of life, but the pain will subside in time.
F: acceptance
A: accept however today goes for me (maybe I cry, maybe I don’t)
R: I move forward

Or this, but it sometimes isn’t credible

C: Relationship, now ended
T: I had 18 months of feeling love and happiness, which I hadn’t felt in forever.
F: Grateful
A: Don’t rush to put it behind me
R: accept where I am

Of course I would like a magic model that fast forwards me 6 months from now when I can feel less-bad about this relationship. I also would like to stop thinking about him but he presents even in my dreams.

Any advice appreciated. Thx