1st trimester when will it get better?

This is my first pregnancy, I am 9 weeks and 2 days. I am CONSTANTLY exhausted. I can't even tell you the last time I wanted to do anything let alone have sex. The boyfriend wants it all the time and I feel horrible for never wanting it and putting it off. I know he's starting to feel like I'm using the "pregnancy/I don't feel good card" way too often but it's literally the truth. Are there any good articles out there that could kind of enlighten him to how I'm feeling. A lot of people have told me they had a higher sex drive while pregnant while mine has been a complete zero since day 1.