Movie from the 90s where a couple have alien bombs inside of them but they dont know.?

My memory is sketchy as well. I don't remember some of the stuff you're saying but it sounds very similar to a movie I watched once in theaters called Impostor. It's about some scientist who is helping build stuff to fight against aliens; and the whole movie is about him being accused of being an alien himself and he's running away from the police or whatever. At the end the main police guy tells him that he knows he's not an alien and they were wrong all along; but that it was his wife. In the conclusion it turns out they were both "alien" creations that had the purpose of not realizing what they were so they didn't draw suspicion but their purpose was to basically be living bombs and destroy other races.