That would be fraud. As a recent immigrant myself one of my fears is that the high-trust culture that makes society work where I am now will devolve into a low-trust one that will make this place more like the third-world country I escaped from.
Mariages blancs for papers have been a common thing throughout the West for many decades now, pretty much since immigration laws were first introduced. It is hard to say that this has harmed the high-trust status of those countries.
You're advocating for committing a felony that could send both spouses to prison for 5 years and cost them 1/2M in fine.