he said "I love you"

My friend, I guess you could say, with benefits said "I love you" while we were hooking up the other night. Of course I didn't responde because it caught me off gaurd. We haven't made anything official, but we do talk a lot, texting most of the day. We haven't met each other's families and we don't hang out with each other's friends.. I'm just wondering could this have been something that he really meant.. or was he just in the moment? I don't think he said it ti try and keep me going with our friendship because I've made it clear to him i don't want anything more.. or I didn't think I did at the time..