How safe is it to finish inside your SO while being on birth control

I'm on birth control and my significant other uses the pull out method. He says he just doesn't want to risk it, we're both not ready for a child but sometimes I would rather him not use this method. I am happy that he is thinking about being safe but I just think that we should be fine If he finished Inside of me. Any words of advice or opinions about how efficient is birth control in regards to having your partner finish in you. I'm on the Depo Provera shot.