When Peter was involved with Joan did he develop feelings for her and possibly want her to leave her husband for him? Since he and the Reader were broke up how serious were he and Joan? Did the Reader date anyone during the break up?

The fling with Joan was just that, a fling. They spent a weekend together. It happened only once. He didn’t develop feelings for her and never wanted her to leave her husband. Peter was heart-broken(you did the breaking up) and looking for company. Joan was simply a distraction. He told you before the two of you got back together. He didn’t want secrets between the two of you.

The reader didn’t date anyone seriously. You went out for a drink with a co-worker. Peter saw the two of you together. That’s the night he met Joan. He thought you had moved on and it broke his heart.