Okay, so I've been thinking about my post and I need to make a revision to what I said. I think whether its creepy or not depends on whether you are an inductive reasoner (starting small and working out to a bigger conclusion) or a deductive reasoner (starting with the big picture and working your way down to the conclusion.) Deductive reasoning says, "Spike has no soul, therefore he cannot be in love," while inductive reasoning looks at some of Spike's behavior in the show and says, "He is clearly in love, therefore somehow, in some way, he must have some spark of something like a soul that allows him to feel." Granted, he is clearly stated not to have a soul yet he also, at times, clearly displays symptoms of love, not just "creepy obsession." Because of that contradition I think either way is a "realistic" view, thus making the "he loves her" view not always creepy.
If it helps, think of the reasoning behind the situation with his mother that we discovered in Season 7. Anne Pratt was ill from TB, then known as consumption. In the 1880s, there was no known cure (there's still not, but strides have been made to temper the illness), so everyone that the then-known William Pratt spoke to told him that his mother was dying. Think about that for a minute -- at the age of 26 or 27 (everyone's still not entirely sure), William was watching his mother die. Slowly. Then, doo-doo-doo, along comes mad-hat Drusilla, and her crazy visions, and her crazy(ER) incesty sires, Darla and Angel(us).
Bonk! Angel(us) doesn't watch where he's going and shoves aside a heart-broken, weepy William, who just had his heart ripped out by a bitch of a woman who "doesn't know his worth." Drusilla follows, and after a creepy moment in some stables where Dru talks about burning fishies, and inappropriately fondles Very!Shy!Victorian!William, she tells him that she sees him, who he really is, what he can be -- that he's effulgent. Drusilla tells him that everything he has ever wanted would all be in his hands, if he just tells her yes. William doesn't know WTF she's talking about -- he's just had his heart broken, and then along comes this beautiful but completely cray-cray chick, and she's telling him, in her own weird, roundabout way, that she wants him. William's sick of having his heart trampled. He wants to be wanted, needs to be needed -- in short, he wants what every good man wants: a woman who loves him for just being him. His mother loves him, but she's his mother, it's not the same. He wants to be in love and have a family, and show the world that he can be a good man.
Things don't work out that way. Instead of the Victorian Dream, he gets a vampire as a sire/lover. (There's still some speculation about who actually is Spike's real sire. There's been some theories that Drusilla actually drained him, but Angel(us) came upon them, saw that Dru screwed it up, listened to her bitch and moan, then finally fed his own blood to William just to shut her up.) He's now a turned fledgling, barely days old, when he takes Drusilla back to his house. He's feeling strength he's never felt before -- he's the Six Million Dollar Man -- or a Kanye West song. Either way, he's better than he's ever been, and the inkling of a thought occurs to him -- if he feels this good, and there was nothing wrong with him before, what could stop him from making Anne feel the same way? Poor Anne, who loves him, and who's dying, and who deserves to live more than anyone else he's ever known -- he can turn her. More importantly, he can SAVE her. He can save the one person who has always been there for him, no matter what.
He turns Anne. But he's still only a few days old, and he's not like the other vampires in his "family." He doesn't seem to feel the same pressure of "evil-ness" that the rest of them do. He doesn't understand that the vampiric demon affects everyone differently. Drusilla as a human was innocent -- she was going to be a nun and then was driven insane right before she was turned. The demon took over any mental faculties she might have possessed and made her an out-of-control lunatic. But William... William didn't seem any different. He hasn't really changed. He just feels free. So he thinks the way he feels will be the same way Anne feels. And unfortunately for him, the demon wearing his mother's face takes that opportunity to shatter his heart -- it breaks him, and he does the only thing he can think of -- he dusts her. He would rather have his beloved mother be dust on the ground than to unleash the monster she's become onto the populace. And the memory of what he did to her haunts him to the point that when he finally gains a soul, the big bad of the year can use that memory to manipulate him, and he's none the wiser because of his guilt.
So tell me again that soulless Spike can't feel.