Okay babe, tell me what time would you considered to have been "wasted". The time you took to get to know them? Spent on dates? Random time spent together?Time wasted on a failed relationship is different than squeezing in time for someone. ..
I mean when I go out with chick X i'm just enjoying my time and just happen to be in chick X's company. If X doesnt work out there is always option Y and Z.
One thing i'll give you on the time issue is the "timing" of things sometime. You may have been MORE interested in someone else but since you were with your current mate and wanna do the right thing you dont pursue it. And then when you and your mate split up all the sudden that other person may no longuer be available