Hmm,he's in a confusing place and 'twould appear that while his mother can advise him, she can't tell him what he needs to know. I wonder, if he did come back, would Luna leave Ron to join him, Hermione, and Lily? That could make for some interesting conflicts. As to a possible wy back, I wager there is one but it's a path fraught with peril and danger, not just to the body but to the immortal soul (legend of Orpheus, anyone?)..
Author's response
Oh yes, Harry's situation is anything but simple. I don't think anybody, living, dead or undead, will be able to advise him anything in this question. He will have to sort it out by himself.
Knowing Luna, my more or less educated guess to your question will be a firm "no". She wouldn't want to break them apart, even if her own happiness would depend on it.
The legend of Orpheus is an interesting idea, definitely worth considering. However, I have another idea I'm trying to pursue first.
Thanks for your support!