Okay, so here's my "diabolical plan"...
There's a verse which you will undoubtedly recall in which Christ states that wherever your treasure is, there will your heart be also.
That's my primary angle here and also what I'm considering making my tagline/signature thingy, too, incidentally.
Have you ever gone fishing? I stink at it, but it's something most guys seem to just LOVE to do (I'm also not a great fan of eating fish all that much so...). However, Christ also said that He'd make His followers "fishers of men" even though He was something of a carpenter and called Himself a Shepherd among other things.
If you're only going after one fish, rather than just using a net or dynamite, most folks use a fishing pole and some bait or a lure of some sort. Different lures work with different fish, but there's more to it than just that.
Once you get a nibble, you have to be patient and wait until they really get a taste of the bait and then you set the hook with a jerk on the line.
But even AFTER the hook's been "set" into their jaw or whatever, you often times have to "play" the fish--giving it room and space (letting some line out and releasing the tension on it's resistance) and then reel it in some until it pulls away again...
This process repeats itself until the fish either tires out from pulling, it gives up the fight, or else the line breaks from too much tension/force for the line to hold.
I think he's still on your "fishing line", but it's just too much mileage and "force" to expect him as hurt as he is and as horrific as the whole nightmare is/was to him to simply give in or let you "win" the fight on your terms. (Not that you're being demanding with him in any real way, I'm just trying to speak more from the "fish's standpoint" there). I think you need to use the little bit of connection you still have with him to "coax" him into investing in you and back into the love he's still got in his heart for what ya'll had together.
If you can get him to meet you for coffee somewhere...or do things like this meal thing you're still doing, but somehow get him to put a little ante in the thing like going with you to purchase the food or helping you prepare the meal(s)...if you can do things together with your son on neutral ground like a park or shopping...little things...things that require him to "invest" just a little of himself along with you...I think it will stir the coals and embers that are still there and glowing some.
I don't think it's even remotely fair to pressure him to go all in or have you move back in or pretend that it's all gonna be "ok" or whatever. I just think that he still loves you and you still love him and whether he can see past his own pain and your betrayal or not, you can still love him however possible and FIGHT for the little chances you can get to not only show HIM where you're at in all of this (which he likely is not in confusion or doubt about from the sound of things I'm guessing), but also to help him love you back in ways that won't hurt so much to do so.
Even if he NEVER recovers from all of this the way either of you would wish (worst case scenario) you'll still have to both look back and render an account for how you loved and tried and fought/contended for the marriage and for healing of one another...or else...for how you simply didn't. And there's a lot to be said for how far putting up a good fight for what's right and best in your own heart goes with not only YOU, but also the person you're at odds with. Even an actual ENEMY will often respect a real heartfelt struggle to survive or thrive. And he's said himself that he's no enemy. And you knew that already. So fight for your kids but also "fight" in a fisherman's gentle and wise/cunning way to get everyone back in that boat together the way a family should be. I think he needs that kinda like your son does.
What does your inner sense/gut say to my post here?
RSVP
(P.S. When I end with "RSVP" that's my way of asking for direct feedback, as in: "Please respond if you would")