If you love some one unconditionally then you can let her go, if she comes back then she was your, if she doesnt then she was never yours to begin with.
Any partner can leave and not come back at anytime. So, according to the popular statement quoted here, that means your partner "was never yours to begin with” no matter how long you were both happily in love? Sorry but I just can’t buy that. If my wife leaves and never comes back, she was still ‘mine” for 33 years. Might just be a semantics game, but there you go.
M: A really long time. Crisis: 5 years. She's still worth it.
Life is never made unbearable by circumstances, but only by lack of meaning and purpose. -Viktor Frankl