The whole time they were together, the relationship was good and it worked, but there were some things he didn't do to the best of his ability. Now that he has lost her, for whatever reason, he realizes that he loves her so much that he will do whatever it takes to get her back because she "means so much" and he will give her absolutely everything he has to give if she would only give him another chance. He realizes now that it's time to show her the best of him, because he finally sees that she is the one and deserves his whole heart.
The whole time they were together, the relationship was good and it worked, but there were some things he didn't do to the best of his ability. Now that he has lost her, for whatever reason, he realizes that he loves her so much that he will do whatever it takes to get her back because she "means so much" and he will give her absolutely everything he has to give if she would only give him another chance. He realizes now that it's time to show her the best of him, because he finally sees that she is the one and deserves his whole heart.