Used Lasso tool to roughly crop a section of the background, copied it to a new layer, and free-transformed it to fit the frame size.
step 2 of 4
Put the cropped layer on top of the source image. Then, created a layer mask on the cropped layer, and used a black-to-transparent gradient to blend the two backgrounds together.
step 3 of 4
Cropped and added married couple on their own layer, scaled and blurred them to emulate the depth of field used in the source image. Then added a curved adjustment layer to bring up the lighting on the man's back to better match the lighting in the photo.
Used a soft brush to paint a shadow under them, dropped the opacity to about 40%. Then, cropped and added the butterfly, and added two shadows under it - a general shadow from its wings, and a more precise shadow under its body. That's it.