Quid pro quo is Latin meaning “something for something” and means “I will do ABC if and only if you do XYZ”. I do not think Quid pro quo is part of a healthy marriage.
An unhealthy “exchange” that happens in marriages is “I will ignore you doing ABC as long as you ignore me doing XYZ”. Of course, no one actually says, “I will ignore you getting drunk if you ignore my overeating” or “I will put up with your overspending if you put up with my porn use”. However, the fact these “agreements” are unspoken does not make them any less real.
I used the word “ignore” to explain this, but often that is not how it plays out. Both spouses gripe about whatever their spouse is doing or not doing, but they only gripe, they don’t really push for change because they are unwilling to change the thing(s) for which they are getting a pass in return.
If you see this in your marriage, and you’re tired of it, start working on your sins. That may not result in your spouse changing, but it will free you from the contract to let sin slide, which is a great starting place for a better marriage. Once you’ve dealt with your sin, you’ll be in a better place to talk to your spouse about their sin.