In the bedroom
“I love you” (during sex)
While he might be genuinely professing his love for you, if he says it during sex it's more than likely been prompted by that thing you are doing with your body/tongue/finger.
“I really like you”
He’s falling for you and although he’s not brave enough to use the other ‘L’ word (love) just yet, he wants to gauge if you are feeling the same way.
“Maybe we need to slow down”
He’s not referring to your bedroom technique, he’s indicating that things in the relationship are getting serious and he’s not sure if that’s what he wants. Maybe he’s not ready to give up his single status or maybe he just needs some breathing room. In any case he’s using “we” instead of “you” because he doesn’t want to hurt your feelings, but what he’s really saying is you need to back off. Ouch.
"So how many guys have you been with?"
It's always tricky delving into the murky realm of past relationships, but this comment usually indicates that he's looking for reassurance that he's the best person you've ever been with. Be careful - his ego is in your hands.