There’s certainly more to it than we are conscious of. Whether that other stuff is purely chemically driven, or it is driven by non-conscious thinking, I don’t know. I also don’t know the balance, on average, between conscious thinking and unconscious stuff in selecting a partner. I suspect it varies widely.
Your question suggests that it is more “evolved” to make such decisions based on personality instead of looks or wealth or whatever. Think about this—evolution makes mistakes—branches of a species that die out. How can you know that an evolutionary change such that will be better for us?
I suspect we know a whole lot less about relationships and attraction than we think we know. I am not at all opposed to non-conscious factors in these decisions. I don’t think you can calculate relationships.