I Don't Want to have Sex with my husband

Since I've become pregnant, sex is the last thing I want to do. I pretend to be sleep, or fake not feeling well so he won't even ask. I feel horrible about it because I know he wants and needs it. He is an OTR truck driver so he's only home on weekends. I know he is tired of jacking off to porn, but my body just isn't up for it. I will try atleast once during the time he's home, but he can tell I'm not really into it. I don't want him to step out on me, but I don't think I could blame him if he did. I don't know what to do...Please him and be unsatisfied???