Husband no interest in sex

I've been married for a year, my husband is 28 and has no interest in having sex with me. We have sex once a month at most. Amazingly enough last month we got pregnant from the one time we had sex. I don't know what to do. I'm unhappy and feel so unwanted. I always have to make the first move, I've tried several things including dressing up and nothing seems to make him more interested in sex. I know he still looks at porn and masterbate a so its not a complete lack of sex drive it just seems to be me he lost interest in. I've talked to him about it and he always says it's not me, it's him. But he still doesn't do anything to try to work on it. Any advice?