The quiet masterbauter

Here's the scoop: I work nights and my boyfriend works days, so our sex can be pretty erratic. We still have sex at least every other day though. One morning I came home from work and was tired, so I went to sleep while he watched TV next to me. When I woke up, he told me he had masterbauted to porn while I was asleep. I'm just curious what everyone's thoughts are, because I'm not sure how I feel about this.