It goes against the entire idea of monetary sacrifice as a signaling mechanism for the buyer. Cheap diamonds are an antithesis to the signaling.
When my partner and I were married over 10 years ago, I bought her a ring and diamond for ~$7k. We were younger, and not so wise. With time comes wisdom. It now sits in a fire safe to be made into a pendant for our daughter; my partner now wears a $20 platinum band from Amazon, and I (occasionally) wear the $10 tungsten ring we bought when we were married (which is bookmarked for easy replacement if damaged or lost). Life is short, don't expend effort on something that doesn't matter. Take a trip together you'll both remember for a lifetime instead.
When my partner and I were married over 10 years ago, I bought her a ring and diamond for ~$7k. We were younger, and not so wise. With time comes wisdom. It now sits in a fire safe to be made into a pendant for our daughter; my partner now wears a $20 platinum band from Amazon, and I (occasionally) wear the $10 tungsten ring we bought when we were married (which is bookmarked for easy replacement if damaged or lost). Life is short, don't expend effort on something that doesn't matter. Take a trip together you'll both remember for a lifetime instead.