Fiance is 6'3" and I am 5'6" - What Size Heel?

Hey ladies. Sorry I have so many questions. I am in between 5'6" and 5'7" inches. I was planning on wearing 3 1/2 inch heels, but I am afraid I won't be too comfortable in them. If I decided to go with a 2 1/2 inch heel do you think our height difference would look odd? I'm not sure if it'll look better to be closer in height or further away (might look cute even, lol). I know there isn't a right answer and it's preference, just curious what others have done in this situation? Thanks!