Respect his wishes without taking it personal, give him the space he has requested.
I think it is partially a gender thing: women tend to like a sounding board to talk out their frustrations; men tend tend to like to crawl into a cave, nurse their wounds, and reflect on what they could have done differently. As with all generalizations, doesn't apply to all.
Also, if it becomes a persistent pattern, then it is time to have a sit down, calm discussion outside of such situations about what it may be doing to your relationship, and how to address the issue. My wife used to give me space -- unless the job began intruding into her life -- until, as she put it, "I feel I cannot even touch you most of the time. The job is killing you." So we decided we should take the risky big plunge, and me take early retirement without fully knowing whether we were yet financially secure enough to do so. It all worked out, with her continuing her job, me consulting until we had enough laid away to be self-sufficient. And as she frequently said, "if you had continued working full-time, the stress would have killed you within a year".