<img src="http://images1.wikia.nocookie.net/__cb20120423060057/mlp/images/9/9c/Spike_and_Sweetie_Belle_partying_S2E26.png" width=640 height=360>

So we've basically determined that Spike is attracted to every species other than his own at this point.
Growing up away from other dragons really did a number on him.