On the contrary, it's more important to be able to reconsider your strong opinions.
> It is harder to move away from what you consider right in ethical sense
Why marry if your ethics are different?
> what is important for your self respect
Unless it's an abusive relationship, I can't imagine a situation where the self respect can be involved. Usually it's just the ego whining about getting what it wants and disguising it as "self respect".
> We are supposed to be emotionally invested in the whole marriage thing.
There's a wide spectrum of emotions but most of them aren't required in a relationship. As the OP's article says, focus on kindness and appreciation.