No pleasure with hubby

Ever since i got pregnant with my first child i havent felt pleasure in having sex with my hubby im now on my second pregnancy but i only have sex with him to satisfy his needs, i feel no pleasure at All, my husband is very attractive very well groomed and dresses really good, i love him very much hes my everything but im not interested in sex with him, i havent had sex with anyone else but when im alone and i start feeling myself i feel pleasure i get horny makes me wAnt to watch porn and i feel so good. I dont understand why i dont feel pleasure with him its been 2 years like this now and i feel horrible because he feels rejected