is sex important in a relationship ?

so me and my fiancé are engaged. but are sex life isn’t how i’d like it to be. we haven’t had sex in a couple weeks and used to, he would always want it. recently he acts like he could care less and saying it’s because it knows I want kids but doesn’t want to be “trapped” with a kid if anything happened between us? I feel like it’s effecting our relationship. idk what to do. it makes me wonder if i’m satisfied anymore...idk I have a lot going through my head recently and I need advice!!!