if Russia invades, you do you

[Ostap]

Goddamn, the women of Ukraine are not (bleep) around. And how about the woman who went to war to be with her husband? I mean, people, the phrase "relationship goals" gets thrown around a lot nowadays, but that's next level. Yeah, that's not even in wedding vows. You realize, the priest is like, "You've got to stay together in sickness and in health, but if Russia invades, you do you."
link with timecode The Daily Show with Trevor Noah

Hello! What does "you do you" mean here? "You two have sex"? If so, what's the meaning of the joke?

 

[SoothingDave]

No, it's not about having sex.

"You do you" means you do whatever it is that you think is appropriate. Be yourself, not acting according to how others think you should act.

 

[Ostap]

No, it's not about having sex.

"You do you" means you do whatever it is that you think is appropriate. Be yourself, not acting according to how others think you should act.

And, do both of "you" refer to the same person?

 

[SoothingDave]

Yes, indeed.

 

[Tdol]

You can act outside in your own interests, though that is not in the wedding vows. It's not a very funny joke. I think he's finding it hard to be humorous about this.