Your wife needs a new heart and only yours will work out.
"I'll do it," you tell the doctor.
"Sweet!" your wife shouts.
The doctor will tell you that if you donate your heart, you'll die. You and your wife just stare at the doctor.
"Uh huh," you say.
"What's taking so long?" your wife shouts.
The doctor says he just has to scrub in.
"It's been a great 22 years," you tell your wife.
"Yup," your wife says. "Pretty sweet."
You high five. You make one last inside joke about that Seinfeld episode you both like, then you lay down and have your heart surgically removed and reinstalled in your wife's body and that's the end.
Happy Heart Donation Day!