You live in a culture that is constantly pushing you and pulling you and luring you to the edge of immorality. And the power of the external stimuli coupled with the internal desires virtually guarantees that if you have not built sufficient margins away from that edge you will get drawn to it. Then, more often than not, when you allow yourself to get drawn to the edge of immorality you will step off the edge.
See if you agree with this, tragic moral choices are generally preceded by a series of unwise decisions.
Most people don't go running to the edge of immorality, the creep to it one unwise decision at a time. Right?
The chief accomplice in this gradual decent to disaster is this seemingly valid statement, "There's nothing wrong with it!"
"There's nothing wrong with having lunch with him/her. Everyone has lunch!"
"There's nothing wrong with having dinner together, After all, we both work late and we have a deadline on this project!"
"There's nothing wrong with confiding in him/her. He/she is such a good listener and he/she understands me."
"There's nothing wrong with listening. He/she needs someone to talk to."
"There's nothing wrong with just dropping by."
"There's nothing wrong with a hug."
And you know what? Probably in certain individual circumstances each of those statements can be true. But together as a continuum, they each bring you a step closer to the edge of immorality. And once you arrive there it isn't likely to end well.
If you have regrets that center around a moral failure, I am pretty sure you can trace a similar path that led you there.
And if you based your decisions on the "there's nothing wrong with it statement", how did that work out for you?
Since you already have the regret and you can look back with more objectivity, did you really believe the "there's nothing wrong with it" explanation or were you rationalizing something you knew to be wrong?
Are you still making that statement to justify unwise decisions?
What do you think would be a wiser standard for measuring decisions if you are a follower of Christ?