The ring just seems to be balanced on the ring it needs somthing to hold it there.
I agree with the comments about the setting. A ring like this will have prongs, usually four of them, that extend a fair way up the sides of the stone to grasp the widest edge. From a distance, you can very rarely see them. That’s by design–they’re often made of platinum, white gold, or silver, in order to match the diamond’s clarity and differentiate themselves from the gold of the ring. In detail, though, seeing these is pretty important, because the stone will look otherwise like it’s unattached and floating.
Otherwise, nice gold and nice diamond materials. And thinning the woman’s ring definitely helped. You probably don’t need to diamond-encrust the man’s ring, though. Most guys’ rings, including my own, are just gold bands. You know, stoic and simple 
Alright alright alright, I’ll add some prongs. Post should be tomorrow.
Here it is:
PRONGS! PRONGS PEOPLE! PRONGS!!! 