confused on what to do!

So I've been friends with this guy for 5 years and we decided to start dating. And it's a plus because he already know my 10 month old son, so I don't have to have an awkward convo with him. Well the other night we were about to have sex and he stopped me asking if I was on the pill, if he should put two condoms on, and are you sure you want to. I asked him why he was asking me all this stuff. And he said and I quote "well I just don't want to give you another mistake." I told him I wasn't in the mood anymore and he just went home. I don't know how to react to this. My son is not a mistake he was an awesome surprise. I want to talk to him about it, I just don't know how. Can anyone give me and idea on what to say?