I gonna say that I would not think a 56yo and 23yo are necessarily an okay relationship. There is bound to be a huge experiential gap between those two ages and that gap will almost inevitably bring with it a massive power imbalance. The dynamic between a 56yo (man or woman, really) and their younger, less experienced partner is always going to be skeevy to me.
I'm sure it's worked for someone, and they have scads of anecdata to back them up. I have hard time seeing how they could have a functional relational dynamic.