Condoms as Birth Control??

Ok so I know condoms are not 100% a safe form of birth control but I can't get on birth control for various reasons!! Me and my bf want to go to the next level but without birth control I'm wondering if condoms are a reasonable means of birth control if I can't get on anything else?? I know right now the only other option is abstinence which I'm not sure we want to wait!! I can accept the risk of pregnancy and I'm pretty sure he can also!! Just worried about taking that next step..I want to feel safe and prepared as we can!! Anyone use condoms as only form of birth control???