Husband doesn't like sex

I'm newly married… We've only been married five months… And my husband doesn't like having sex with me. He has confessed that he looks at porn and I think he masturbates to it. I have tried wearing lingerie and being flirty and seductive but a lot of the time when I initiate sex he refuses or tells me he's tired. He doesn't initiate sex very often in fact it's very rare. Is there something wrong with me? Why does he like looking at porn rather than being with me? I'm pregnant now but have had a miscarriage in the past but even before the miscarriage he was like this. It makes me feel pretty insecure about me, like he doesn't like what he sees. Does anyone else have this problem?