Mine did the same. We were also living apart at the time (and still are). He told me about the A about a week before I was moving back home. We probably had, in total, about 5 conversations over the phone and Skype after DDay. He had promised me he was going to NC the OW while we figured out what to do and then, in our last convo, I found out he took the A underground. I had told him if he did that I would S from him, so I told him I wanted NC for two months.
I'm now approaching month 3 (in a couple of days) and I haven't heard from him since. He cancelled a flight to see me without saying anything (i got the email from the airline because it had been booked with my miles). Our only contact was FB in which he was manically posting passive aggressive crap that seemed directed at me, so I unfriended him. Once I did that he took himself off of our phone plan. Our lease was up in July and I assumed he moved, but he sent me no forwarding info. My birthday and his MIl's bday came and went and nothing.
Before I met him he broke off an engagement and never talked to the woman again, so he's rehearsed at the cut and run. I like to assume our M meant more to him, but then if it did, he wouldn't have had an A.
At this point I'm assuming that's it and I'm not going to hear from him again. There are no kids and we had separate accounts, so there are only insurance things, college funds and loans that we need to work out and that doesn't require us being in contact (that's why there are L!).
We have some major milestones coming up in the next three months that could conceivably bring him out of the woodwork, depending on how things are going with him. We are also in the same field and have an annual professional conference coming up and he was still debating whether to attend it last time we spoke, so it's possible I could see him there.
But after this much time of NC, I'm okay with not talking again. I don't want any new hurts and I've stopped being curious about what he's doing, if he's still with OW or not. Unless he were going to reach out to me and our friends and family to apologize for being a shit and hurting all of us, NC is a blessing.