Frankly, if you're marrying a person who requires you to spend 3 months on a diamond ring, it may be time to remember an important bit of wisdom:

Never enter into a contract where one party benefits by breaking it.

I'm not knocking marriage or (outright) stating that financial motives may be at play, here, but it's a big indicator if "who your with" is more concerned about what's "on their finger" than about what's "around their arm".