Petrified to have sex

I just had my second and last baby and I'm petrified to have sex in fear of getting pregnant again. My husband is getting a vasectomy in January and we have to wait 3 months after that before he's considered sterile. I'm terrified it's going to fail. I'm terrified that the birth control we use until he's sterile is going to fail. I want to use BC and condoms. I know I'm not going to be able to enjoy it. It's always going to be in my head that our birth control is going to fail. How did I ever have a sex drive as a teenager?