The photo is, I believe, a promotional still from a play JB was in some time ago. Which is to say, it was convenient, not accurate to Jack's timeline.

Jack, being Jack and having a weird sense of personal responsibility and self-punishment, could probably come up with a lot of reasons that are outside of the "good idea for his own personal fulfillment" category for getting married. Conversely, I can see him clutching onto a relationship in an attempt at normalcy that he then can't actually execute on.

The tie-in novels have him owning all sorts of random property around Cardiff in and around that period, which suggests a life somewhere other than under an office, possibly with another person.