Can't use birth control.

My husband and I have been married for almost 3 years and have been together for a total of five years... I have a blood clotting disorder that makes it very dangerous for me to use a pill or the shot or any type of birth control, besides condoms. So basically my entire relationship with my husband we've had sex with condoms. Recently my husband has been asking if we can have sex without using a condom... The idea of this scares the crap out of me because I'm not ready to be a mother... But I do think that it's a little strange that I've never had unprotected sex with the man I married... He says that pulling out will work, But honestly I'm more concerned about getting pregnant because this disorder that I have is really dangerous and it causes miscarriages and can be really bad for my body if I get pregnant without being on a blood thinning medication... I am the one that freaks out every time things start getting hot and heavy and I make him put on a condom... Basically I just want to know if the pullout method is really something that actually can work... Or if I should just stick with condoms...