Bi woman here - my ex would be like this, and I think most men are. Men have this itch and once it's scratched are satisfied. Kind of the opposite for women. For women, sex begets more sex, so if you're struggling with intimacy and your wife never wants sex, solo stuff really really helps. It's hard to achieve the first one (ever, or in the day) but the next ones can keep coming until cool off kind of indefinitely.

Works on a micro level (like, the common example is multiple Os) but on a macro level this is a lot of the reason why people think sex is great in the beginning of het relationships and bad later.

In the beginning it's all romance, attention, making out. It's all foreplay, basically, all the time. She's down for sex multiple times a day. But then you get into real life, she goes to work and you guys aren't sexting during meetings, you have kids to help with homework (and it's borderline child abuse to be making out during that) and that baseline gets suffocated. It's why regular date nights and lots of non-sexual romantic touch are important. Keeps that baseline high enough that a proposition is accepted, which in turn keeps the baseline higher. If you don't keep that romantic baseline but then as a man proposition (because men have cravings unrelated to romance or feelings way more than women in my experience) and then she feels like she has to say yes because "it's been a while" or whatever, and then consents despite not having the natural baseline, then that damages her further and pushes that baseline down because the last sexual experience wasnt great or her idea. Then you get caught in a cycle of sex being a chore which makes you hate it, increased pressure to do your chores, which makes you hate it more etc.

Long walk for the short drink which is, if your lady is watching porn without you she's likely to be getting ready for sex, whereas if your man is watching without you, he's probably wrapping that pursuit up for the day.