Hi GHOSTY. What you've experienced is normal. Couples are not always successful when trying to make a baby. Just wait a little bit and try again. When the couple has successfully made a baby, the female villager will be carrying the infant in her arms when she comes out of the Love Shack. You can also check out All about villager babies on our help site.

Here's another link that you may find useful: If you need help with VVO2.