Gottman talks about betrayal being on a spectrum. Here on this board we're mostly dealing with the most obvious and egregious of betrayals, but Gottman also talks about the tiny ways a partner can betray another, letting them down, choosing work over family time, the SSM. We all have to draw our own lines of what we'll accept and what we won't, and I'm sure none of us are totally innocent of some level of betrayal. I know my H considers the SSM a slow-motion act of betrayal, me turning away from him time after time for years. That adds up. Not to excuse him or anyone... but I do agree that the decision to stand or walk is a very personal one. I know a lot of LBSs (at least the ones here... I'm sure there are plenty who walked away without a second thought) have a total knee-jerk reaction to want things to go back the way they were. it is important to detach your emotions from the sitch (yes, I know! easier said than done) so that you can really think through what matters to you, your values, what kind of person your S is, all of that, before deciding whether to stand or not, and thinking through what standing might look like for you-- there is a whole lot of variety in that space as well.
For Elbereth-- you remind me a lot of myself. I said and felt a lot of the same things you're feeling and saying. For me, the control/boundaries thing was huge and I really didn't understand it. I want to dig into that a bit. (AlisonUK had some incredible posts on my thread on boundaries in the early summer, June/July I think? If you want to find them.)
"You can't come home and spend time with your son if you see OW without quarantining and testing before you return." This is not a boundary. This is an attempt to control his behavior. And it really seems impossible to enforce, anyway. I agree that a restraining order is probably a bit over the top. Also, is seeing OW the only way you think he'd be engaging in COVID-unsafe behaviors? Is it about OW for you, or the combination of his affair AND being an idiot about COVID that is really getting you? (I ask because if it was me, I *know* the affair part would have been a major portion of my feelings about it, even if I couched it even to myself in the COVID part only.... in fact, now thinking about it, I had a very similar situation last Feb., when my H went on a business trip to AP's city and I said if he didn't break it off with her then, he wasn't coming back home.)
Think about this. What if he weren't your husband? What if he was a family friend who wants to hang out? Once you decided you weren't comfortable seeing him for COVID-safe reasons, wouldn't you just... not see him? You wouldn't have to explain anything, even.
So maybe try this on for size: "If you return from this trip and aren't prepared to quarantine in the house and get a COVID test after 3 days, I'll be at a hotel." The boundary protects YOU, it doesn't control his behavior.
The kids make it complicated, I think, especially because you don't have legal rights here. So I would balance it with what is in the best interests of the children. I think you said before he'd been living in the basement-- do you imagine he'll go back there? is that enough distance for you? Can you and the kids wear masks and stay 6 feet away from him at all times? open up all the windows so that you get a lot of cross-breeze? I'm sure you can figure something out. Just remember you only control you.
HUGS.
Me (46) H (42) M:14 T:18, D9 & D11 4/19 - 12/19: series of escalating BDs 9/20 - present: R and piecing