verse
もし今の私を見れたなら
どう思うでしょう
あなた無しで生きてる私を
According to this post accepted answer,
It's still the object marker. The sentence is just not finished and the verb is implied.
However, I don't think this is the case here. As far as I'm concerned, we can leave out を without changing its meaning:
あなた無しで生きてる私 (A)
I've done some research online, coming across the following:
を (Human emotion) marks a noun or noun phrase that serves as the cause of some inward human emotion. It pairs with inwardly-pointed verbs of emotion such as よろこぶ [To be glad]、[悲]{かな}しむ [To be sad]、[懐]{なつ}かしむ [To miss / To yearn for], and [悩]{なや}む [To be worried].
Recovered from wildnihongo
No example ending with solely を was provided, though. From this source, the construction is given by Noun / Noun Phrase + を, which happens to be the case with (A).
The source also notes that this usage of を is rather literary:
(1) を (Human emotion) is very literary and you are unlikely to hear it in spoken Japanese.
This what I've gathered so far from English sources.