I didn't get this the first time I read your post but you're saying that he won't have sex more often because he is jinxed or something for 2 days following each time he cums?

Hell, if that was true I'd have nothing but bad luck! Actually, it goes against the usual understanding that you get an endorphin rush and are happier after sex. Try pointing out every good thing that happens in the 2 days following. if you know something nice is going to happen (maybe you know you will be getting a tax refund this year?) have sex the day before and then when taxes are complete you can say "See, it's because we made love!"

If all else fails, masturbate in sexy ways when he is around and order a new vibrator. I love watching my wife do it. If he sees you or knows you are doing it, it may urge him to become involved. If not, you'll have some great 1 person love making!