A/N: I was originally going to write this as a fic in which Lily cheats on James with Snape, but I just can't ever see her doing that, so I won't write it. This idea literally just popped into my head and I figured I might as well write it. Then again, I can't really see this happening either, but damn it, I felt like writing it and so I did. Even if it turns out awful, there's always worse, right? I hope this isn't too bad, but hey, you're the one who clicked on it.

Set…eh…let's make it their fifth year, before the Mudblood incident. Snape's POV. Sex is implied, but not explicit.

Boomerang

With lithe fingers, she pushes her cascade of auburn hair aside, draping it from one shoulder to the other. I see the hesitation and guilt flickering in her emerald eyes. Such a strange yet typical quality of a Gryffindor; they never seem to possess the ability to hide their emotions. Even when they try, the inner turmoil raging in their minds is always visible somehow. And she's no different, really. I can practically watch the gears turning in her head.

Wordlessly, she sits up, draping sheets around herself. It's always after, when the experience becomes something more than just a foray into hedonism, when her self-consciousness strikes. She's a brilliant witch, no doubt, but she has a nasty habit of making the same mistake numerous times. Or what she considers to be a mistake.

"Severus," she says, the name falling oddly off her tongue, as though she's addressing someone else in the room.

"Lily."

"I can't keep coming back to you."

"Then why do you?"

She looks at me, her expression somewhere between angry and defeated, knowing she can't blame me for her actions. Was I expected to talk her out of this?

"You're not doing anything wrong," I point out, rather coldly.

"Maybe not, but you are."

"You never did approve of my friends," I chuckle mirthlessly. I suppose now she'll think she can use this as some sort of ultimatum, a test to see which side I'm going to pick. Suddenly the image of perfection next to me seems to fade away, and I see a woman just as divisive as any of them.

"I just can't accept the man you're becoming, Sev," she sighs, almost wistfully. For a brief moment, I see the genuine concern flash across her face. Like she's talking to a friend, rather than a disappointment.

"No one's making you accept it."

She's going to get up and leave, like she does every time, like I've let her do every time. Because we're both stubborn and headstrong and in love with each other, but too in love with our own ideals to compromise. Because she won't forgive, and even if she would, I won't apologise. I'm not playing her "me or them" game, not now or ever. I'll miss her when she goes, but she's a boomerang. She'll come back to me, for one reason or another, be it emotional or physical. And I don't much care what reasons she picks, as long as she makes her way back again, I'll know I haven't lost her, not yet.

She'll realise her mistake as she leaves. She'll come back, thinking maybe, just maybe, she can talk me out of this or change me or fix me. We'll start with a talk and then we'll escalate to a shout. Then a fight.

And somewhere along the lines, the anger will fade to passion, or maybe they were both there to start with, we just had to wait for them to bleed together. And I'll ask the same question: "Are you sure?"

And I'll take her lack of response for a yes.

And for a little while, we can set aside our growing differences and be as we were before, like when we were kids but with a new kind of play, something more dangerous, something with strings attached.

And then she'll regret it, and she'll swear to me, or really more to herself, that she won't come back. Or that she can't. Whichever. But she will, and I won't stop her. Because if I do, I'll lose her, and I'll be damned if I drive her away.

"I'm not coming back to you."

"Just keep telling yourself that."

"I won't."

"Sure."

She stares at me, searchingly, for some indeterminate amount of time. Another moment as she dresses. Another sentence as she leaves.

"Goodbye, Severus."

A/N: I know this isn't quite as good as my usual stuff, but if you have a review to leave that ISN'T a flame, I would appreciate it. Thank you!