29 Weeks Pregnant- Needing Sex tips.

So my Husband and I have been together for 3 1/2 Years. We have a 1 Year old & another on the way. I love my husband very much. Always will, but my sex drive is no longer. Idk what's wrong. But I just dont feel the need to have sex. At the beginning of this pregnancy my sex drive was CRAZY, but now. It's like I'm not attracted to my husband. But weirdly I like masturbating but not sex.. I like spending alone time with myself.. I need some help.. How can I spice things up in the bedroom?