How can we improve our sex life?

My bf and I typically have sex 2-3 times a month and honestly I don’t think that’s enough! I would love to do it more , but sometimes I don’t horny that much and idk why. My bf loves having sex with me and every time I want to , he wants to too. But I don’t feel like we have it that much and I would like to do it more often , but idk what’s causing me not to be horny 😕