Not so sure only a guy could answer this...but...everyone is different and his reasoning is unknown. Only thing I could suggest is to straight up ask, why did you pause, what's wrong...talk about it. If you don't talk about it you'll, never know, we can't tell you what he's thinking or why. Best advice I can give is don't be scared, it's better to know, either way, than go on wondering day-to-day, because your anxiety about the relationship will start to cause problems.

GL!