I met my wife in high school and we've both changed quite a bit, and fortunately share similar ideologies now. Politically, we were both republicans because parents -- and then I got interested in Ron Paul, which led us both to anarchism.
One point of contention, albeit small, was religion. I was Christian, then agnostic, then atheist -- while my wife stayed Christian for some time. I would drop some objections and arguments here and there, and she always seemed dead-set against changing her theist position. Then one day, she seemed to open up about it out of no where, and now she's an atheist. Of course, this is no bash towards theists, but I think it's an interesting parallel to statist beliefs and the process of communicating these ideas to partners.
As you mentioned, it can take years and that's even with a person who's intelligent and open-minded.
That's why I think attempting to attract a person with closer ideals is always a safer bet. ;)