The Mexican romantic fantasy “With You in the Future” pretty much blows the “fantasy” part of its equation.

A sentimental “Peggy Sue Got Married/It’s a Wonderful Life” riff with a sprinkling of “Back to the Future,” “Contigo en el futuro” is about a couple whom Cupid revisits when they’re in the process of splitting up their belongings and abandoning their their twenty+ years of marriage.

Cupid, who “never f—s up,” offers them a mixtape from their youth and gives them “five songs” that they’ll hear that night to sort out erasing their present by interrupting their pasts.

“We’re like ‘The Terminator!'” Carlos insists to Elena, and Elena insists to Carlos. It’s a clumsy device that hobbles the film’s opening act and allows Cupid to overwhelm its finale.

But the sentiment in between is so winning it almost compensates for that. Writer-director Robert Girault taps into that universal cinematic truth — that for all the pain that life and romance hold, it’s always better to have lived, loved and lost than to never have loved at all.

Elena (Sandra Echeverría, radiant) dreamed of musical fame in her youth. She fell for Carlos (Michel Brown, brooding) and a conventional home and family. The day we meet her, she’s putting post it notes on everything she’s claiming in their house. He comes home to discover that he’s not just given her the house, but she’s taking most everything else as well.

That’s what happens when you say “I don’t want anything that reminds me of ‘us'” (in Spanish, with English subtitles) in the heat of the moment.

One thing they agree on? “Cupid got it wrong.”

But the ancient cherub (Mauricio Barrientos, not quite funny) who interrupted “my first vacation in 500 years” to haunt them would beg to differ. He “never f—s up,” he insists, more than once. Still, he gives them the mix tape and drives his new Corvette into the past, a Valentine’s Day in the early ’90s when teen Carlos (Fernando Cattori) met skating lead singer Elena (Mariané Cartas) of Elena and the Skates at his girlfriend’s Valentine’s Day party.

Carlos and Elena from the present will show up at that party and torment, trick, hoodwink and commit armed robbery to keep their youthful selves from falling in love.

Carlos from the present knows the history of soccer over the last 20+ years, which he might share with his dorky, sports gambling former “wingman,” Chickless (Harold Azuara, funny) if the aptly-named Chickless gives him a hand. And adult Carlos knows his life would have been easier had he stayed with his rich and connected girlfriend Cristina (Aminta Ireta) way back when.

Elena has the pain of present day loss and wondering “what might have been” had she stuck with pop music.

A cute touch here is that a key moment in their romantic past was meeting at a rock concert by the legendary Mexican band Maná, which by the way, was just announced as the first Mexican band up for admission to the Rock and Roll Hall of Fame.

There are other cute touches, and funny bits in that Valentine’s Day party. And every so often, the script and the way the players perform it punches us right in the heart. The older leads grasp what they’re losing, the younger ones remind us of that first blush of true love.

Some such moments are surprises here, and some we see coming. But getting that part of this Back to the Romantic Past to End Our Romantic Future right makes a stumbling story of Cupid as God of Love fixing all that ails a couple perfectly bearable, and occasionally damned sweet.

Rating: TV 16+, gunplay, profanity

Cast: Sandra Echeverría, Mariané Cartas, Michel Brown, Fernando Cattori, Harold Azuara and Mauricio Barrientos

Credits: Scripted and directed by Roberto Girault. An MGM release on Amazon Prime.

Running time: 1:31