@LaAlan - I wonder if this is why. It was the first I ever heard of it, but I suppose it makes sense. It's also one of the reasons why I decided to go with the 4 diamond one, which my husband and I just ordered online. I hope it will stack well or perfectly with the small love, but I haven't heard anyone mention anything about it previously.
While we are on the topic, my husband and I decided to hold off on the engraving because as it turns out, the 4 diamond only allows 4 characters, which includes spacing as characters, making it extremely difficult to engrave anything meaningful on it. We wanted to do his FIRST INITIAL (space) HEART symbol (space) MY INITIAL - (this is on our wedding bands with mine the opposite), but that's 5 characters in total when you include the spacing between the heart. We might have to go with no spaces, but we didn't know how that would look aesthetically so we decided to hold off until we can go inquire in person in an actual boutique for the engraving.