Need crux data, HINGMAN.
Not that I'm inferring you SHOULD enjoy it (nope - one woman's meat is another's poison), but I note you failed to mention or even hint anywhere what exactly it is about 'sexting' that you find so unpalatable and such a (clearly emotional) turn-off? Did you, for example, feel that you and he were somehow indirectly welcoming/instigating a DEMOTION of relationship status by going through the motions of what, say - possibly to your mind - nigh-on complete, often (but not always) debauched strangers, i.e. "doity one-night-stand-ers, stayers and tempters" tend to do?
If not, then - what? We're all big girls and boys round here, you can tell us. Plus you're completely and utterly anonymous as well as not the first with this problem by a long shot.
Me, I see his insensitive insistence on flicking what so patently is a newly-identified, raw nerve of yours, and his seemingly blinkered dual standards (ref you not understanding HIS needs when at the same time he's guilty of the exact same thing) - and now even implying direct albeit mild threats - as a (not-so-)subtle cry for help in terms of flagging a problem and wanting to shove your face closer to it so that you'll finally take how he's feeling seriously, rather than his just more honestly spelling it out (or maybe he's not emotionally articulate?). Clearly you're already perfectly aware that he's self-servicing while you and he do this.
All the above is on the one hand good news (he's actively demonstrating his fidelity), but - here's the bad news: it's a 'cowardly' hint on his part that, with his obviously needing such 'assistance' (for putting paid to his only-to-be-expected mental frustration and physical discomfort), yet your meanwhile refusing to be The Partner-Helper, then MAYBEEEEEE... (job-share vacancy?). This explains why the uppage of ante in the form of "maybe remain alone". Note 'ALONE'. Note 'REMAIN'. But also note 'maybe'.
"Maybe the cute puppy will get it!....all depends on YOU, luv!"
He's lonely (are we surprised?) and, *at this point*, merely bluffing....trying to put the frighteners on you (desperate is as desperate does). He wants relationship promotion in line with the (sorry but it's true) over-grandiose, falsely reflective status labels. And he earns more than you - correct?
He can't hack this set-up any more.
...I mean: "Though we meet frequently like 5-6 times a year for 7 days to a month break." UGH, STIFLING, GIVE THEM SOME AIR FOR GOD'S SAKE!
Seriously, though - can *you*??? Do you not appreciate how downright WEIRD it is at this late point of play and marital products/achievements (incl having had kids) to still be doing long-distance like mere boyfriend and girlfriend? Are you surprised to learn I was sat here as I read of your inappropriate set-up, only one paragraph in, going, "WTF?!"?
However, since your set-up has prevented the level of closeness and openness that one would ordinarily expect between husband and wife after 11 - EEE-LE-VEN!!! - long years and having produced kids together, it's then altogether understandable that either one of you (cough!MAINLYHIM!) would act-out instead of just saying whatever it is needs to be said, straight. Or HAS he already tried spelling it out but you overruled and vetoed him?? (I note the logging out, i.e. the cutting-and-running you did there.) Is he diving straight for emotional coercion tactics or are they a now-desperate, last-ditch resort? RSvP again.
So I agree you should have a proper, lengthy, sit-down discussion about it (in-person or over the phone) until you can find a compromise or whatever alternative (e.g. phonesex?).
Me, I note how you were perfectly okay with the sexting until he ratcheted it up too far. And I also suspect he ratcheted it up deliberately, KNOWING (because he knows you and your history) that you'd find it repugnant (aim, fire, bullseye!). In other words, sexting is NOT the end but just a means to an end. A ruse of a one at that.
Be forewarned, therefore: As said, methinks he's done as much long-distance-ing as he can possibly stomach by now, at this ridiculously protracted point....which is basically what he's too tentatively, timidly, thus manipulatively, trying to signal and contrive into place. I think he wants you to feel you (and the kids) should follow him out there before it's too late....cease playing commitmentphobically at marriage - as if there's such a workable thing as part-time marriage (writing on wall confirms NOT) - and just get stuck into the real thing. Furthermore, whether consciously or not at this point, he might have got it into his head to prepare the ground, future justifications-wise, for sexting with someone(s) else as could lead......
Having pushed and nagged beforehand, AND coloured your refusal as a huge crime (hardly!) by you against him, he could then - if caught - turn around and claim, 'Well, if *you* hadn't refused to be my virtual partner then I wouldn't have HAD to have blah-blah-BLAH...' (- even boring myself now :-p....you know the crap cheaters come out with, I'm (COUGH!) sure. But, going by the amount of time he expended in nagging you over it before issuing that threat, it's definitely YOU he wants and...only if he doesn't finally (FINALLY!) get it/you would he then, simply out of sheer desperation and loneliness and positively screaming needs, think about seeking it elsewhere.
Or not. It might all be pure bluff no matter how frustrated and over-hard-done-by he gets to feeling. Or not. DUNNO! You never know what that sort of unrelenting stress could push an otherwise upstanding individual to doing, do (COUGH!) you.
I'll stop farting around, shall I? Your, I suspect, 'brilliant solution', modom, has gone full-circle to where it now has entered Problem All Of Its Own territory. It's called negative self-fulfilling prophesy. And yours includes a hoop too far, as in, 'Let's see how long *you* can go without committing adultery on me!....bucko!'. ....But then you got used to the perks (e.g. house mainly all to yourself), little knowing what other, bigger and better perks were there for the taking as would have been putting your perks right into the shade.
Evidently, 11 - ELEVEN!!!!! - long years is 'how long'. WOW, WHAT A PRINCE, WHAT AN IRON MAN! Are you going to give the poor s*d a break yet and climb all the way in, finally? Or are you going to wait until your "safer" half-relationship does what halves do and finishes halfw- NOT EVEN halfway through?
*Enough!* already. Whether it was your brilliant avoidance plan, like I suspect, or his and he now doesn't know how to resituate the goalposts to where they always should have been - it's run its course and your marriage is about to lay down on its deathbed.
(Do feel free to correct me if/wherever I'm wrong, won't you.)