The boyfriend dilemmas are always the hardest. I don't ever advocate breaking up another couple's happiness just because you want to try and find your own. There's a reason people get together in the first place, after all. BUT, just because two people are together does not mean they're living out their happily ever after. She deserves to know how you feel so she can make the best decision for her. It's not fair for you to decide that the other guy is more right for her instead of letting her decide, you know?
And parents should be the least of your worries, but I can't exactly talk there. I say talk to her first then you two can figure out the parents together if you do decide to try things out. Don't let silly politics stop you from being happy.