@TheMarksman
>She's wearing a ring
>it's on her left ring finger
>Protagonist's hand is sweating
>implied by title he's not the husband
Regardless if waving man is husband, son, or neighbor. It's safe to assume what we are looking at is a small form of cheating.
I say small, because we get no more contextual information to imply anything beyond her sending updates on underwear. Maybe thats how she gets her kicks with her husband away? Maybe they're fucking? No one knows!