I agree with what you're saying somewhat. As you said, if you love someone, you want them to be happy so you want to do things for them. Absolutely. I'm saying many people think that love is just something that "happens" or its a one way street---I married this person, therefore I should be happy and it should be easy. I.E. many people aren't putting in effort, and when they think they are, they are really only putting in effort as a means to an end for themselves, and not the other person or the overall health of their relationship.
You do have to sacrifice for the good of the other. The problem with your second half statement is that isn't always easy. There's a lot of things we want to do that take vigorous determined attempts. Love, regardless of relationship, takes sacrifice for the good of the other. Sometimes that is difficult and takes determination. (It is NOT enabling, however....for example sometimes my sacrifice for the good of my wife involves the reaction that she will be mad at me in the short term, but we'll both benefit in the long term. People also confuse self-sacrifice with enabling bad habits or things. Think parents who let their 30 year olds mooch).
Like sports. Just because someone wants to be an all pro and wants to give the effort doesn't mean that the effort isn't vigorous and determined, and sometimes difficult.