If I had a SO, I'd change my view however necessary to see viewpoints I haven't seen, as I would with anyone. As for culture, I'd gladly throw away any part of it that doesn't define me, though I couldn't really say what that is, and I'd be open to adopting any part of a different culture that doesn't compromise my core values or make me uncomfortable. There's no way I'd compromise my core values for anyone.
Do you think a 3-way relationship can work and would you be a part of one?