If he/she saw the grass was greener, how long should you give it time ...

[fun2bewith]

...before you can make a move. How many months should you allow for them to continue with the new person before you could make any impact on him/her by what you say or do; before any words or letters that you write will have any impact?...This is now if you want him/her back of course....

[listen_to_me_please]

never, forget you knew them but scientifically speaking, the "in-love" phase can last 2 years.

[USMCHokie]

Infinity...

[mistakemaker]

When you find out, let me know

[shayan]

never wait for someone who deliberately leaves you and breaks your heart. It makes absolutely no sense, in any sense. Emotionally or rationally.

[Kic]

If you have to do this, you're best off waiting until their relationship is over completely AND the ex is over it (you shouldn't be a rebound).

 

Since this could be months or years, the best thing is to assume it will never happen and try harder to improve yourself and meet other people.

[2010_Sorry]

I would not make a move unless you know with 100% certainty that he/she has learned from the mistake. With that being said, I thought the grass was greener once, then realized that the cows go there too. Never again!!! It took me 2 months to realize it... but 18 months to finally shake the other man.