How often do 30yr old guys usually want ?

how often does a 29yrs old guy normally want to have ? my husband and i have been together for almost 2 years, we used to have every day, but now im lucky if we have once a week. Im 18yrs old and it seems like i have a way higher drive then he does. also i have found on his computer, i just dont understand why he doesnt want to have , but he can masturbate to ??? some advise would be mucho appreciated.