Some things are not what we imagine. Maybe there is a fact behind them that we don't know.
We think that such love cannot be reciprocated, but we don't know that he is also loving with heartache.
There is no reason, if you love someone, you just love them.
Even if we are separated, we will still miss you.
However, when some love cannot last a lifetime, he is willing to let her go and let her pursue a more lasting love.
He knew that she had been sad, that she thought he didn't love her, and he wanted her to think so.
He knew that this would be better than another kind of pain.