engagement rings

I don't have an engagement ring because Hubby didn't really proposed formally. So I told him to not bother get one for me. But after seeing some engagement rings over the internet today, I'm having regrets of not owning one. It doesn't need to have lots of diamonds, one is good enough for me. Diamond engagement rings are really the saleable nowadays. Maybe I can have one on our anniversary or my birthday. What do you think? He can have it ordered online, I have an eyecandy already.