In the couple's ledger, Bethany's balance is -$80,421.10, largely money she owes Danny from grad school. Sometimes she pays for more things out of pocket in "the real world" to bring down her debt in the private books. The plan is their startup's eventual success will wipe out the balances.
"Sometimes it will feel unfair in the short term, but you have to trust that it will be fair in the long term," said Danny.
They do use some tricks to make it easier, like separate bank accounts. To cut down on bookkeeping they also say a random number between one and 10 when they haggle. The chore still gets done, but only if their two numbers match is there a payout, which they multiply by 10 to make up for only one in 10 bids matching.
"Normal people have perfect good approximations of this," said Danny. "This is just nerd level turned up to 11."
For two people who met online and share advanced degrees in computer science, it's a great system.
"You need to really appreciate that money is utility, you have to trust in the math so much," said Bethany.
So what about sex?
There's no bartering in the bedroom, they say.
"I don't think we've ever disagreed," said Bethany, because there's never been a time when only one of them was in the mood.
Family therapist Terrence Real has no problem with the cash component. "They use it as a gauge to ask the critical question... 'what's it to ya?'" he said.
However, there can be dangers if kids are involved. "If I was their child and I learned that they were bidding over the task of putting me to sleep I might get upset," said Real.
Another wrinkle is that the couple hasn't factored for how Danny didn't give birth to two children. He's also earned more in his life, giving him a bigger pot to bet with. They're mulling over whether to give Bethany a lump-sum payment to fix the imbalance.
It sounds mercenary, even cruel. But there are ways within the system to show affection.
Recently Danny and Bethany haggled to see if he would drive her home after a long day of work or if she would have to ride her bike. She bet $15, and he intentionally "lost," so that he could do her the favor.
Communicating in a series of brief instant messages, she replied back with a smiley face emoticon, 21st century love boiled down to two characters.
--By Ben Popken, NBC News