It's pretty self-explanatory, I think. A person (the singer) has fallen in love with somebody, but this somebody doesn't know. However, the singer doesn't let go of this somebody in their mind, and ends up building this illusion of a relationship that simply isn't true, and "paints a picture" of this person that, really, they don't even know; at least, not as well as they'd like to think. The person they'd imagined in their mind was in actuality nothing that they thought they were.
At first the singer knows this, but eventually, the "lie became truth". He didn't want to see the fact that he'd never been close with this person that he's created this whole fantasy around, and doesn't want to accept the fact that it is just a fantasy, and gets lost in his own illusion... and as a result, he ends up hurting the person he fell in love with in some way.
It's pretty self-explanatory, I think. A person (the singer) has fallen in love with somebody, but this somebody doesn't know. However, the singer doesn't let go of this somebody in their mind, and ends up building this illusion of a relationship that simply isn't true, and "paints a picture" of this person that, really, they don't even know; at least, not as well as they'd like to think. The person they'd imagined in their mind was in actuality nothing that they thought they were.
At first the singer knows this, but eventually, the "lie became truth". He didn't want to see the fact that he'd never been close with this person that he's created this whole fantasy around, and doesn't want to accept the fact that it is just a fantasy, and gets lost in his own illusion... and as a result, he ends up hurting the person he fell in love with in some way.
Honestly, it hits pretty close to home, for me...