My wife used to like regular (at least daily) sex (before we were married and had children, who are 6 and nearly 2). In the last few years not so often.
Anyway, I have bought her a few vibrators over the years. Sometimes she uses them after sex, I think she needs more clitoral stimulation than she otherwise gets (sometimes we have oral sex first instead).
I work on computer from home and tend to work most at night (after midnight) because there are fewer distractions. Anyway, last week came back from a long walk with family. She told me she was going to bed. Her phone went off so I brought it to her, she had got her vibrator out and was about to masturbate. I asked her what she was doing, anyway she wasn't keen to have sex, but eventually said told me to go and have a shower and then come back and have sex. I did so and came back, she said she was finished already and was only joking about sex after shower, and in any case we had sex only yesterday, and she was premenstrual and just wanted to use the vibrator to make her go to sleep. I got in a mood and left and worked till about 4am. The next morning she seemed to ignore the fact I was still trying to sleep, waking me up by leaving the bedroom door open. I made a point of ignoring her for several days.
Eventually we went away for the weekend on Friday, came back yesterday night on better speaking terms (we haven't actually discussed any of the aforementioned).
This afternoon, she told me she was tired, I said 'yes me too'. Her response to this obvious hint that we should go to bed, was to tell me she was going to bed, and not to forget to pick up our son from school. When I went in to our room later, she was asleep with vibrator under her pillow.
I didn't indicate that I'd noticed, but told her that I wasn't going to cook the dinner (she'd asked me to cook before she went to bed), and she's noticed that I'm in a bad mood with her. I don't object to her having a low sex drive (although obviously it would be better for us if she didn't), but I don't think it's reasonable to eschew sex with me for masturbation. Am I being unreasonable?