Is there a possibility with being pregnant in this situation?

My boyfriend and i had sex for the very first time after being with each other for 4 years. He put it in for like 3 seconds and pulled out he said he didnt come but felt somewhat of a wetness on the head of his penis. He says when he usualy comes he ejaculates alot. His penis was clean when he took it out there was nothing at all on it or anywhere else everything was dry. He says hes sure nothing came out but im just worried.