How long should I expect this to take?

I came out to my parents more than four years ago, when I got into a serious relationship, and they still think this must be a "phase." It's exasperating. They took a full four years to agree to meet my girlfriend and they still see me/call me less than they used to. (I live in a different city.) When I told them that my girlfriend and I are getting married, it took my mom several weeks to muster up a "congratulations."

I understand that most parents need time to adjust - mine are pretty old-fashioned and churchgoing, and certainly never imagined I might be gay - but I'm wondering, I guess, whether there's still a chance they'll come around, or whether they're a lost cause, after being given four years.

Also: any advice on how to get through to them that 1) This is for real, and 2) They're hurting me by trying to ignore it?

 

I've tried to have serious conversations with them at various points over the last four years - the key message being, this is jeopardizing our relationship - but little action seems to come of it. Agreeing to meet my girlfriend was a big step, but it's not like we're getting together regularly at all. I guess I'm just curious how long other people have waited for their families to come around.