It’s tricky, sneaking around on someone you love.

A mental lapse could find you spilling the beans about a plot twist, or repeating a hilarious punch line — only to realize that the knowledge came from the episode you watched without them, despite your promise to wait faithfully.

Netflix, where TV episodes live at your convenience, commissioned a survey into (literally) serial cheating — whether someone would furtively stream a show they’d agree to watch together with their spouse or partner. Slightly more than half said they’ve considered it, while 12 percent said they’ve already committed hi-def infidelity.

Netflix calls this “stream cheating,” a clunky term that undercuts its prim tut-tutting about not being held responsible for “any trust issues, lovers’ spats or marital troubles that arise from watching ahead of your partner.” Please. They want this.

Other findings?

Almost six in 10 said they would likely “cheat” on the main TV if home by themselves. But one in five brave souls said they’d watch in bed while their significant other slept. Five percent said they would do it in the bathroom. (Fans of “Breaking Bad”?)

As in legitimate infidelity, most wouldn’t let on, but 14 percent said they’d “feel so guilty that they would have to confess.”

As in more intimate betrayals, video-dultery requires keen attention to avoid suspicion: About one in 10 said that while rewatching an episode with their sweeties, they would “fake” any emotional responses necessary.

Pity the poor “Downton Abbey” fans who mourned one evening too soon over Matthew Crawley. □