In some cases, it does.
For example, would you "let" your spouse commit suicide?
Would you "let" them quit their job and become a drug addict?
Would you "let" them have an affair?
Would you "let" them do anything that puts the marriage/relationship in jeopardy?
Because bringing home a Chow or a Basset Hound is grounds for divorce! At least in my household.
You might be able to stop your spouse from committing suicide, but many people cannot, and that is not anything on them.
I do not know how you would stop a spouse from quitting their job or becoming a drug addict, I suppose if that is what is happening, you can try to manipulating them by threatening them with leaving if they do not seek help, or sign themselves into treatment. For all of that, success really depends on how much the addict wants to change, and not how much those that love the addict wants them to change.
I suppose some people might not mind an open marriage where both sides can have affairs. That is really weird and dangerous, but that would be the only way you could let
them or not let
them. I think most of us would not let
them have an affair, but some will anyway, and then it is really about how much you are willing to take. You might not let
them have an affair, but you might let
them off, and not break up the marriage over it. I think if two people agree to be true to each other, then it isn't about letting the other have an affair, that isn't a question.
"Would you "let" them do anything that puts the marriage/relationship in jeopardy?"
I think if you approach the marriage this way, you are in danger of being so controlling that you will put the relationship/marriage in jeopardy.
I think that being partners, being in a relationship, being married means making major decisions together, and getting a dog is a major decision. I think that it is better for the spouse who truly cannot abide a particular dog to put their foot down before it comes home. It will be easier in the long run. If it is always only about 1/2 of the equation, the relationship is no where near equal. Some people are ok with staying in a relationship that isn't equal.
I make all my decisions with respect to my four-footed dependents. When you have kids, decisions have to be made with respect to them. And when you have a serious relationship, decisions have to be made with respect to and ideally together with them.