4. You realize after your date with Guy A that you DO want to see Guy B exclusively..
3 is best tiny and innocent.
you understand her reasoning behind hiding a guy she acted like was giving her the big stick from the rear on the dancefloor...you just don't want to see it. My guess is that aint all they did that night..
If he will still stay with you after you told him you have feelings for your ex, then dont worry about whether or not he's hurt. If he is, he will work through it, if hes not, whatever. IF he had a problem with it, he shouldnt have asked..