rosabug, I'm your age, and was approaching 50 when my 20 year marriage ended. I'm ok, still single as I still feel too vulnerable to try dating. I have some amazing friends and the freedom to please myself far outweighs the occasional bouts of loneliness I feel.
I won't pretend it's a bed of roses, financially mine and my adult kids lifestyles are very different, but generally it is so much better than putting up with a loveless marriage.
Think of it this way: if you stay, you know you won't be happy in a year's time, if anything you'll be more unhappy than you currently are, but if you go, you are opening yourself up to new possibilities and happiness.
I need to feel that I could date again, and I won't fall apart if it doesn't work out. I have met some lovely men, but I put my guard up and back away because I'm scared of being hurt. But hopefully I will get my emotional strength back to start afresh with someone.
I don't feel old or past it at 55, I certainly hope I meet someone, but the crucial thing I've learnt is that being on my own is fine, most of the time it's good. This surprised me, because I've been in relationships from my mid teens.
There is a special type of loneliness that exists in an unhappy marriage. I truly thank God every day that I no longer experience that.