Her ending is like the most tradwife fantasy imaginable where you both retire to a farm together and all her dialogue is about how genuinely happy she is to do so. So I cannot agree that you're shaping her into anything when it's literally what she wants.
People can change, I don't know. There's that idle dialogue (with Astarion and/or Wyll) where she basically states that she prefers flings to commited relationships, but maybe she just hasn't met the right person yet. I think there are other similar parts too, but I can't quite recall them right now. As I said, I haven't done her romance subplot, and this is just how she seems to me as just a companion. Maybe it's a facade. Or that Shar thing.
Anyway, I haven't seen that ending, but if that's correct, there's little point getting upset about the person she is/was rather than appreciating the person she becomes, if that's someone's thing.