The relationship hit a bump when Zubyk decided to switch sides. He quit the NDP and started working with the federal Liberals, then joined the provincial party to help Christy Clark as a backroom strategist.
"It wasn't easy at first," said Munro, who is Mike Farnworth's volunteer communications chairwoman. "But when you're in love with someone, you know all aspects of their personality. I know where his heart is, and we agree on more things than we disagree. It was more difficult for some of our mutual friends."
That external tension caused them some recent trouble, when rumours circulated Zubyk was helping Munro on the Farnworth campaign. Zubyk thinks the rumours were deliberately spread by supporters of NDP leadership rival Adrian Dix.
"I have tons of NDP friends, but some people in the party think I'm a traitor, so these kind of tricks are played sometimes, which can be frustrating" he said.
Friends in the rival camps tease them about how much "pillow talk" is traded in the downtown condo.
"The rules are fairly simple -- I don't tell Brad anything I wouldn't say to a journalist," said Munro. And Zubyk reassures his team that even an inadvertent slip-of-the-lip is not a problem.
"We trust each other implicitly," he said. "If I do happen to blurt something out, I don't think Marcella is going to Twitter it."
They both think their relationship is a timely example of how civility, respect and kindness can be embraced in the bare-knuckle culture of politics.
"I grew up in a family where there was lots of respectful disagreement," said Munro.
"My grandfather was a Saskatchewan farmer and diehard NDPer. My grandmother was a Conservative. Every election, they would drive together to the polling station and happily cancel out each other's votes. They did that for 50 years."
"It makes for interesting parties at our place," Zubyk said. "Our friends see we're helpful and loving with each other, even if we are working for different sides. Couldn't we all use a little more of that?"
Hard to disagree. In a province of deep-seated political anger and division -- and at a time when the Arizona shootings have heightened tensions everywhere -- Munro and Zubyk are proof that love is the most powerful force of all.