Our
thinking, feelings, thoughts evolved and changed from our
experience. Its not matter of breaking promise because in the first
place, its silly if he were to believe you. Not saying that you
don't keep to what you had promise him, but in life,
nothing is absolute - so is love.
From our experience, we gain the neccessary wisdom about our
personal love with a partner. Practical? Half correct - the right
word is Discovery.
In our early relationship, we knew NOTHING about relationship at
all. The guy/girl we picked and chose to be our bf/gf - there is
simply too little comparison between him/her and others. We knew
nothing because we only listen to what the heart speaks.
As we mature in love - our vision widens and we discover that to
make a relationship successful, we have to see a whole picture
instead of plain I-love-you-you-love-me concept. 
You are being put-off not by him, but by a decision you made ages
ago because now if someone similar like him were to appear, you
would outrageously reject him because this isn't the kind of guy
you are looking for now. Time change, people change, money talk.
Your changes are normal.
P.S: Remember the time when we used to think that we looked cool in
a hairstyle/clothing/etc? We took a photo and five years down the
road, we look back and we feel that we looked so stupid. This is
exactly what is happening. Our preception, thinking and taste
changed. It's part of 'growing up' - in love.
Cheers
