I don't know what you men have got with this 'age' thing.
When I was in my early twenties, I dated men my senior because they were intellectually my equal - and I know why they date me - it was because I looked like a Barbie Doll and they wanted to 'show me off'. We both benefited from this as I got a better education and they had their ego's stroked. Many of them are still in the circle of my friends and we laugh about the good-old days. I married the wrong man - my age - and didn't finish my study of medicine, but have a wonderful daughter and grandson to make up for that mistake.
Later, when I was divorced, I met a young man in his twenties while I was 35. He treated me like a queen and swore he'd never go out with anyone younger. Well, he's married to a woman his age and they have children now too. So... the world turns and life goes on.
I know that each man and woman have this 'thing' about the 'other guy or girl', but it's stupid to think that this is the only reason for someone to move on. We all mature at our own pace, and when that happens, we make other choices in life - we just have to accept them and cope and also respect that when it happens to our partners.
The pain of a break-up and future rejections are also a part of life, as normal as breathing, and happens to all of us. There is nothing unique in this at all.
The things you do have control of in life is through learning from your mistakes and how you plan your future without dwelling on the past. This is hard and takes more time for some than it does for others, but you too will get through it. Caring and missing are normal emotions but we don't always share this part with others for self-preservation and not through meaness - so accept this and go on.
Don't blame the other men you see - they make their own mistakes and have their own problems, probably worse than your's - so give them a break.
Take the goals you set for yourself and put them in perspective and start working on them.
We will be here to help you go through the phases with the combined experience on this site, but what you do with it is your choice.
Good luck dear, and I hope that your healing process does not take too long. Vent here any time.

No blame, no excuses, only acceptance will help you on your way now - you too will survive this, I promise.