Here is a thought that I had when you were talking about the client who had a huge 2 carat ring on her finger. MY guess is that it may not necessarily be a natural, mined diamond. A lot of times when you see rings with stones this big, they aren't real but are diamond simulants (very nice ones) set in the same quality of setting as any other swanky ring.
Nothing wrong with simulants/man made diamond alternatives at all. In fact, I'd rather opt for that nowadays and get the setting I really want. Use it as a placeholder stone but get a great setting so when you're ready to upgrade to a mined diamond, you still have your setting and the sentimental value it provides. Think "starter ring" like "starter home".
But, you be happy with what you have if you have sentimental value. A lot of women who got married when they were younger didn't do big rings like girls do now. And I can guarantee a lot of these big rings are not mined diamonds.