Introverted Sensing... or?

Hi everyone! :tongue:

I was having trouble applying a certain character trait to MBTI theory and was wondering if you any of you guys could help me out. My first boyfriend is an ISFJ (Si, Fe, Ti, Ne) and I've always noticed that he tends to prefer to IMPLY things to get a message across, as opposed to saying things upfront. He was definitely not the direct type and much preferred to beat around the bush. He had basically confessed his feelings to me implicitly on his blog, via songs/lyrics and every other alternate way you could think of. I wasn't sure if this was a self-esteem issue, and that he was merely trying to test the waters before making a move or whether it had something to do with his functions.

I know a guy who acts in a similar way, who I suspect is an ISTJ or ESTJ. Do you think this "implying" tendency has anything to do with Si/introverted sensing?