how many times do yall have sex?

with your husband? ive been w my husband for 4yrs and i feel like we dont have sex anymore. well more like he no longer wants me since he does porn and other womens pic more than me. we only have sex 2-3x a mth, sometimes 1. we used to have it everyday, went down to 3x a week, 2x a week, once a week, to 2-3x a mth. is it normal for long term marriages to not have much sex anymore? i still want it 3x a week, but he doesnt.