[oldnewbie]

IMHO
Your husband married you to have 100% of your time and love (5hrs a day excl. sleep/work[he thought so]), so in a month works out to around 60hrs and sex every other day

in reality,
with kids,work ,others you are lucky to be to giving 10 hrs a month of your time to him, which is much lower to what he expected

and with 10hrs and 21 days/month(menses,not your fault) and what is going to happen to the passion between two of you ,and how many opportunities for sex will he get?

IMHO
therefore he will feel deprived, and will want to have sex with you whenever there is an opportunity

don't be frustrated , put yourself in his shoes and you can understand him better