Sex and pregnancy

I'm 16 weeks 3 days pregnant with my daughter. For the past few weeks sex is almost the last thing I want to do. I want to make love to my husband and I want to have sex but when I think but it all I can think about it being to tired or not really even wanting to be touched! We still have sex regularly and my husband know that a lot is different and it seems to bother me way more than him! Any advice to spice up the sex or to get me in the mood?