Movie where someone's wife is secretly a monster

Question

I watched this in the late 80s, early 90s. It had a tales from the crypt feel. It was in color and quite short.

The story is about a man and his wife in a room, they're opening some drink and chatting. He said he has an old story:

The show goes back many years ago where he went outside and was walking in a back alley. There was some homeless man he knew as far as I remember. And that one time someone was close to the homeless person. As he gets close to see what happens, he sees that the person on the homeless man is some kind of monster that is eating him (or just killed him, I don't remember).

The monster makes him swear that he will never tell anyone, or he has to kill him.

Then it goes back to the room where the guy talks with his wife and he said that something happened to him a very long time ago but now it probably doesn't matter anymore and he goes to get a box. In that box is a paper drawing of the monster he made. He wife suddenly drops her drink and starts to shake / transform and tells him that he promised he would never tell it to anyone (she was the monster).

Answer 1

It is Tales from the Darkside: The Movie

...Along the way, Preston stops to relieve himself in the back alley. While there, his friend sees and then shoots at the gargoyle monster, but it brutally severs his hand and decapitates him. Preston witnesses the horrific scene. Terrified, he tries running away, but the creature corners him. It spares Preston's life when he swears never to reveal what he saw or describe its appearance to anyone. The monster then scratches Preston's chest saying, "Cross Your Heart," then vanishes. Preston is traumatized and confused, but bound by his oath, can say nothing about what happened.

The horrified Preston runs into another alley where he sees a beautiful woman (Rae Dawn Chong) passing by. After grabbing her, he assures the woman she will not be harmed. The woman, Carola, claimed she became lost while going to meet friends and was searching for a taxi. Preston convinces her to call a taxi from his apartment. While there, Carola cleans the gargoyle-inflicted wound on Preston's chest, then they make love.

Preston's life soon improves and his struggling art career becomes wildly successful, mostly thanks to Carola's connections. They eventually marry and have two children. However, Preston is tormented by memories of the gargoyle, and his vow of silence weighs heavily on him. On the tenth anniversary of his and Carola's first meeting, as well as his friend's death, Preston breaks down and tells her about the monster. Carola appears uncomfortable by Preston's revelation and then emits a heartbroken wail, saying he had promised never to tell anyone, revealing herself as the creature that killed his friend.

With Preston's vow broken, Carola can no longer remain human and begins transforming back into a gargoyle. Their children, now awake, are terrified as Carola writhes in pain as hideous-looking arms and legs burst from beneath her human flesh. A terrified Preston pleads for Carola to change back, but she cannot assume a human form again as her transformation back into a gargoyle keeps on continuing. Their children are screaming in their bedroom as they also transform into gargoyles. Carola, now fully transformed back into a gargoyle, wraps her wings around Preston and the couple proclaim their love for each other, but with the vow broken, Carola is still reluctantly forced to kill him by biting his neck, before remorsefully flying away with her gargoyle children. The final scene shows the three gargoyles now turned to stone and sitting upon the building ledge, staring down at the city with sorrowful expressions.