Husband and wife both work in DC intelligence community, probably both in uniform. At a party, a senior officer gets wife drunk and into bed. Husband sees what's happening, but can't stop it due to rank issues.
He's a computer security and surveillance expert, so he can get video of the whole thing. He uses it to get senior officer in trouble. Then he files for divorce and goes out of communication for a couple weeks.
The senior officer loses out, but the wife also loses her job and is reassigned to the middle east. Her plane crashes in the Mediterranean; no survivors.
A couple years later, Husband has retired and is living on a sailboat. By chance, he finds his wife living on an island near where the plane crashed, with no memory of her previous life.
Read probably 3-10 years ago, probably here or on lit.