While my wife and I struggled with our sex life (meh, still struggling) we planned to have sex one morning. That morning she decided against it so I went in to shower and took care of myself. She then showered, came out and invited me to bed. I explained to her that I was all set since she told me sex was off so I masturbated in the shower.
She was flabbergasted. It never occurred to her that I masturbated. She said that she wanted me to save all my orgasms for her. I explained to her that I had been masturbating since I was 10 and unless she was ready to meet my sexual needs (3-4 times a week while we were struggling to get it done once per week) then I'd continue masturbating.
TX-SC is right... I think most women don't realize the fact that masturbation is probably the bulk of a guy's "sex life" and would be shocked to learn that.
Similar experience here, in my marriage. I don't think my wife realized how often us guys do this, or why.
Once she did, I think a little competitiveness came over her, much the same way somebody reacts when their partner gets hit on. Basically, mate-guarding, which is funny, because she mate-guards me from myself!
I've learned to be a bit more open about it, and although I still don't try to get caught, if I do, it often leads to some good times.
She's still very LD, but I'm glad she sees it in a positive light. I've seen one too many posts on this board about people with LD spouses who get upset, or downright angry, if their HD spouse masturbates. Hell, my LD wife masturbates occasionally, and although it DOES bother me a little (as in, she has much less interest in sex than I do, so why not save it for me?) I still recognize it as being healthy, normal, and also as something that is quite different than sex with your partner.