Would you be upset if you walked in on your husband masturbating?

I walked in on my husband of 9 years masturbating while standing over the bathroom sink. In all the years we’ve been together I’v never witnessed him in the act. Idk how to feel about what I witnessed. It was mid morning and he just returned home from the gym. I was in the living room with our young children. I only walked in on him because the bathroom door was locked but it wasn’t fully closed. His backed was turned to the door and he was standing over the sink. For context we have a decent sex life. We’re intimate 2-5 times a week. We have 4 young kids ages between the ages of (7,6,2 and 5 months). My husband tried to initiate things last night but I was too tired. Although we’re not lacking when it comes to being intimate, I still feel weird about what I saw. Am I wrong for feeling grossed out?