feeling insecure and unattractive

My boyfriend and i are expecting our 2nd child. When i was pregnant with my first, i found out he was on a dating site and flirting with other women. Although it never went past that I felt betrayed and hurt as any woman would. Fast foward to 4 years later, we have made lots of progress. But lately im just feeling unattractive and extremely insecure because its like he never wants to have sex. i have gone through every text message, phone call, email, browser history, fb. You name it, ive looked through it. I cant find any sign that hes cheating, but i just dont understand why hes in not interested having sex. he is 10 years older than me (im 26), so i try to take that into consideration. but i just cant get past this feeling that hes not attracted to me. i just feel like crying. im horny alllll the time and getting it once every 2 weeks if im lucky