what is the meaning of 'you both lose' in the paragraph?

Question

First of all, your boyfriend or husband is not your “opponent.” Thinking of him that way during a discussion will compel you to treat him accordingly. If all you’re trying to accomplish is to get your point across and win the argument, you both lose.

The above paragraph comes from the book Make Him Beg For You Attention, I'm not quite sure the meaning and the grammatical facts of it.

What I thought about the meaning is that both of your aims, get your point across and win the argument, will be unsuccessful according to the contents. But if so, what is the grammatical structure of the sentence? Why not using you lose both?

If I see the sentence alone, I think 'you' is a determiner and 'both' as a pronoun which represents the couple is the subject and lose is the verb. So the meaning will be both of the couple lose

Answer 1

In this context, the pronoun both is used to disambiguate the subject, you. English uses the same word for singular and plural pronouns in second person. In other words, if the sentence read "you lose," one would assume the author meant the singular pronoun, referring only to the person reading. The author actually means the reader and her partner, so the subject is plural. The sentence could have read "the two of you lose" or "everyone loses."

Answer 2

The author means that both you and your opponent will lose if all you're trying to accomplish is to win an argument. He loses because he's lost the argument, you lose because (probably) you have alienated someone you want to have a relationship with.