low sex drive

I feel like since being pregnant and even a couple months before my sex drive has just bottomed out. My fiancé on the other hand seems like his sex drive has just sky rocketed since I’ve been pregnant. He’s not pushy and doesn’t get upset when I say no, but I can tell he’s a little disappointed when I turn him down. It isn’t really uncomfortable yet as I’m only 15 weeks but I just have no desire to do it. Do y’all have anything that’s helped boost your sex drive?