TTC but don't want to have sex 😩

My SO and I have been trying to conceive for a short 3 months and I'm finding I couldn't be less interested in having sex. Obviously it is a vital part of falling pregnant but I'm just not into it. It's nothing personal against him, I love him and wouldn't want to be with anyone else I just don't want to have sex but desperately want to fall pregnant. Does anyone else get like that? Did you just wait it out or did you try spice things up? We have been together for 7 years so perhaps the 7 year itch?? Please help 😔