In 2008, Jen began seeing singer John Mayer, who by then had become widely recognised as a Hollywood womanizer. Despite the headlines, the two dated for 11 months and seemed to be very much in love; John confirmed as much in an interview with Playboy after their breakup, saying, "I wouldn't undo it, man. Because if it had worked out, I would have reaped the benefits. I would be sitting here saying, 'What I have when I go home is the thing I've always wanted.'"
John also alluded to still having feelings for the actress after their split. "We just have a regard for each other's feelings that is pretty intense. It's been a deep relationship, and it's no longer taking place at all. Have you ever loved somebody, loved her completely, but had to end the relationship for life reasons?"