I really love song interpretation, and especially with U2's work because it's not always so direct - everyone has a different take on it and it would seem nobody is wrong! You can twist the words to fit every situation, young and old may have different opinions depending on what they're going through etc.
So after seeing such amazing ideas put forward, some in ways I'd have never considered, I hope it's ok to share mine on UV... It's quite blunt, but maybe a different twist - I see more of a dialogue about an unhealthy affair rather than a breakup of a marriage...
I actually like to split the song into two different people, as if this is an insight into both their perspectives… At times it’s ‘Bono’ singing to a girl/someone who’s involved in an affair, providing a sort of guardian angel vibe…At times it’s the person and their involvement/emotions during the unbalanced affair
"Sometimes I feel like I don’t know
Sometimes I feel like checking out
I wanna get it wrong
Can’t always be strong
And love it won’t be long"
How the affair began, can’t always be strong to your beliefs, sometimes it feels good to be wrong, to do something wild, at other times you want to quit it, check out. It won't be long until it comes to an end...
"
Oh sugar don’t you cry
Oh child wipe the tears form your eye
You know I need you to be strong
And the day is as dark as the night is long"
This would be 'Bonos' view, so the ‘sugar’ he’s talking about is the girl, telling her to be strong, knowing that it’s difficult
"
Feel like trash you make me feel clean
I’m in the black can’t see or be seen"
The girl is feeling dirty after the affair, a little used and invisible, can’t see the way out, she’s speaking of someone/something that gives her hope, someone that can see her and make her feel clean
You bury your treasure where it can’t be found
But your love is like a secret that’s been passed around
‘Bono’ again, singing of how the girl was innocent and beautiful within (some form of treasure), had a guard up against everything (can’t be found), until the affair/abuse, now the love she had to give has been taken and lost its beauty, like a secret told enough times lessens its value
"
There is a silence that comes to a house
Where no-one can sleep
I guess it’s the price of love
I know it’s not cheap"
Again, this is the end result of the affair, silence, emptiness, so much on somebody’s mind that they can’t sleep, but there’s nobody they can say anything to. The chorus etc is all about asking for their path to be lit, the way out of the darkness to be made clear
"
I remember when we could sleep on stones
Now we lie together in whispers and moans"
Remembering a time when the relationship, friendship could be out in the open, but now it’s resigned to a secret, just sex, nothing else.
"
When I was all messed up and I had opera in my head
Your love was a lightbulb hanging over my bed"
Back to the guardian angel, something providing a glimmer of hope. Opera is dramatic, love and death etc etc, so the person is claiming that when all they could see and think of was the worst case scenario, the end of the world, they still had that little lightbulb reminding them of hope.
The last two lines bring to mind two people who are essentially using each other to quench a thirst. Brilliant. So, this verse sounds like a slightly boozy, highly stimulating encounter, to me. 
about what I've always believed Bono was on about. My disclaimer on this is that apparently Bono isn't entirely sure lol (or willing to share). 
Your version never would have occurred to me, either, but after reading it, I can see where you have drawn that conclusion. The "punctures the skin" line in particular, I'd never through of it in that way before. I've never heard of heroin being compared to red wine though, unless he was using poetic license to create a sort of metaphor? 
