This song is about a man's (i'll use a male figure since the singer is a male) inability to appreciate and see the true love he had for the woman he was with before they ended their relationship. Most of the inability to appreciate or feel the love was massked by fighting about stupid things, the desire to prove the other person wrong, and the growing frustration due to an inability to see eye to eye.
Now that they have been broken up for some time, the enger and frustration have subsided, and he is beginning to remember the good, pleasant things. Those memories are sticking.
He says that he tried hard to let her go, but some kind a madness is swallowing him whole. By that, he means: as the enger and frustration are leaving him, the void left by the absence of those feelings is filled with the love he has for her, which is causing a huge shift in his perspective on things. That's why he says that when he looks back at all the crazy fights they had, like some kind a madness was taking control. In other words, he can't even believe he was arguing with her because, again, love is replacing anger and frustration and it's hard to bring back the memories of anger vividly enough to eliminate the returning feelings of love and clearly remember and justify the reasons for all the arguments and unhappiness. Therefore, he feels he didn't have control over his own actions.
But now, with frustration beging gone, he is seeing things much more clearly. That is why he says he has finally seen the light. She, on the other hand may have known, even in the midst of furious fighting and unhappiness, that he would come to this realization one day. That is why he says, he finally realized what she means.
Then he begins to show confusion. He says, "now, I need to know is this real love." This means that, at this point, he does not trust his feelings. He knows the grass is always greener on the other side. When he is with her, they fight, they're unhappy, and want to separate. But when they're not together, he feels the love and the need to be with her.
And the final portion of the song, he's reaching the conclusions and seeing through the confusion. He demonstrates that by saying that he's finally seen the "end." He knows he can live happily with her until the end, but he does not expect her to care because he understands he may have reached that conclusion too late.
However, he wants her to know that he realized he made a mistake. He understands he needed to love her and show her the love while he was with her, while it counted the most. That is why he shouts: "I have finally realized I NEED TO LOVE."
With this final realization, he begs her to come back. He is desperate and only she can rescue him. The fact that he says, "come to me, just in a dream, come on and rescue me" indicates to me that he's in pain so strong, a dream of her coming back would serve as a morphine pill taking away the pain for at least the duration of the dream. MADNESS!
