I expect any multiple-choice question is too challenging for most of this website's visitors. Or maybe there just isn't a lot of kissing in little kiddie superhero films.
But I can certainly step up with some answers.
I'll reply to all these off the top of my head but probably add half-a-dozen more choices for any given point.
Below are just the responses which happen to occur to me this morning.
Here goes.

1. What are your Top 3 Favorite Movie Kiss Scenes?
   The Country Girl.
   William Holden & Grace Kelly.
   From Here to Eternity.
   The Burt Man & Deb Kerr. Can't omit it.
   Casablanca.
   Rick & Ilse. Ditto.
2. What are your Top 3 Favorite Movie Sex Scenes?
   Cool Hand Luke.
   Joy Harmon washing her hot rod in the driveway while the cons watch.
   Pat Garrett & Billy the Kid.
   James Coburn in the washtub with two Mexican girls. Pretty racy.
   Plaza Suite.
   Bigshot movie exec Walter Matthau seduces suburban housewife Barbara Harris just by rattling off names of celebs.
3. What are your Top 3 Favorite Movie Scenes in which a Husband, a Wife, a Boyfriend, or a Girlfriend got cheating?
   Doctor Zhivago.
   Old family friend Rod Steiger mauls young Julie Christie but she clearly likes it. Liked it so much that later she tries to shoot him.
   Straw Dogs.
   Similar situation. Susan George is married to a dull professor (Dusty Hoffman), but one of her old boyfriends secretly corners her. She doesn't say no.
   The Cincinnati Kid.
   Tuesday Weld returns home to find Ann-Margaret brushing her hair while The Kid (Steve McQueen) is still in the inner bedroom. She knows what happened with just a glance.
4. What are your Top 3 Favorite Movie Scenes in which a broken-Up couple reconcile with each other?
   The Best Years of Our Lives.
   The legendary scene where Frederick March returns home from the Air Force.
   Perfect Strangers.
   Estranged husband & wife Robert Donat and Deb Kerr both return to their bombed-out apartment at the same time, during a lull in the war.
   Random Harvest.
   Out-of-his head soldier Ronald Coleman famously finds his way back to Greer Garson.
   Thanks for posting your poll. Good stuff.
   Paul P. Powell, Pool Player