Sun and Moon

The lyrics set the scene of a dark departure of two lovers. At first it seems to indicate that she is saying goodbye to him. He clearly has something to be sorry about, perhaps he did something to hurt her and she couldn't forgive him (you gave me your answer).

I still can't decide why he seems to think her can assert she'll never get over him, though.

A love that never had a chance to blossom. He cannot give his heart to her even though he wants to, something is keeping him. This was an attempted relationship and was left unfinished, hence "I'll never get over you, you'll never get over me".

Thanks to deed02392, GraphicSiren, and Serinarae808 for the timely explanations on the meaning of this sad song. Without their insightful interpretations I wouldn't be able to offer the following possible details for the lyrics this late in the game. Anyway, just putting my thoughts out as the lady who walked away and struggled for the past 7-9 years trying to make sense of all the pain this song carries. Here it goes: @GraphicSiren identified the words from the song's chorus to be a play on gambling as a metaphor for falling in love. I too think he took a gamble, it failed, and as a result he lost her but it wasn’t entirely his fault. He put his heart on the line by declaring his feelings to her and in return she hid her true feelings from him, claiming they were never anything more than friends. She wouldn’t admit that she loves him too. Her decision to hold back her true feelings after he finally opened up to her was enough to push him away for good, he came to the conclusion that she wasn’t ready for anything real to happen between them if she couldn’t be completely honest with him. In the beginning she was the one who wanted something more than friendship and she let him know how she felt for him when they first met a long time ago, only he didn’t take her serious back then so they drifted apart. Time passed and they reconnected once she reached out to him after having not spoken to each other in years. He responded to her effort and it seemed like they were falling in love all over again. She thought it was too good to be true and ultimately walked out because she didn’t believe he was being sincere due to how he had treated her in the past even though he apologized for his mistakes.

Then as @Serinarae808 said, theirs was a "love that never had a chance to blossom. He cannot give his heart to her even though he wants to, something is keeping him" from going all in or someone/something is now holding him back from being with her. Their last hug was goodbye and that hug was also a deep beautiful experience of real love no words could describe. Her pride won’t let her keep chasing him and he’s equally stubborn in his own ways. They are flawed human beings who won’t change, there’s nothing more either of them can say or do to save the relationship at this point. It’s over because they both are unwilling to take any more risks despite knowing deep down in their hearts that if one of them would just give in they might be immensely happy together.