third person

-as a man
what do you do when you had/have feelings for a woman, but the woman is unavailable.
I'm sure some of you will try to move on and meet other woman, but can you let go that easily? If you think she might be the one?
Do you look for certain aspects of that person in other women? How do you guys cope with those feelings?

-as a woman
If you know the above about a man, but he is still courting you and you see a lot of potential in this man.
How do you deal with this fact.
Will you give it a try nevertheless in these modern times? Would you feel less?

-as a couple
When you feel you have the perfect man/woman and everything is going great, he/she is the one for you. You have build up a life together, but then,
as it often goes with love, his/her feelings have slightly faded and he/she starts to have feelings for someone else.
You know this, but he/she does not know you know this. If you tell him/her you know, it will mean the beginning of the end.
What would you do? Do you stay in your perfect little world, or do you face the fact that you might not be the one for your "one"?