I hear you, OP. Divorce turns not only your current life inside out and upside down, but the rest of your future, too. To adjust your view of the rest of your life is extremely difficult. Like looking through a window to find that the familiar and beloved view outside has been replaced with a landscape you don't recognise. And a sense of discombobulation, that everything that was certain now is uncertain. It is truly as if you thought you were in wondrous Oz but the curtain is pulled back and someone you don't know anymore says "Only joking! Hahahaaa! Did you think you were going to live in this Technicolor world forever? No, my dear, no! Back to bad dates, small home, and worrying about the future for you!" And just like that, the door on Technicolor Town is slammed in your face.
I do not think that people who have never experienced the sheer pain and horror of divorce can possibly understand.
I, too, see long-term married couples all around me who are now reaping the benefits of a few decades of married life, shared finances, and shared bills. They all have lovely houses, great marriages, and lots of nice holidays. They have their troubles, too, but they have each other and really nice lives.
What can I say? It simply is not fair. I was betrayed, too. I have noticed that people who had no choice in the end of their marriages seem to feel it worse than those who had a mutual break-up or who were the ones to initiate the split. Those people tend to be fine about dating again and remain optimistic about relationships and marriage, often wishing to marry again, and doing so. Meanwhile, the mere idea of another marriage or live-in relationship after my abusive marriage to an angry, uncontrollable bear has me gibbering in the corner.
I see these long-term happily married couples bumbling around in their little worlds, knowing nothing of the scars that divorce inflicts, and to me they seem childlike and innocent. When you divorce after being blindsided, I believe you cross the Rubicon into a world of new knowledge that you can never forget. I think that it's very hard for divorced people and people whose first marriages worked out to communicate. It's not their fault, and you know that.
I think for me, the hardest thing has been coming to terms with the sheer unfairness of it all. Of course, I know that life is not fair. I know it rationally. But to be thrust into such a totally different place from your peers, through no fault of your own, feels more than unfair, it feels cruel. I can understand why people talk bitterly of their divorces decades later. Divorce reverberates for the rest of your life.
I think you should take a step back if being with these friends is hard for you, OP. And when you do see them, you can keep it short-ish. Can you meet them for coffee and cake? I wouldn't be accepting any couple-y dinner party invitations and the like. You could stay in touch via text and stuff. You don't have to spend hours hanging out with them in their perfect world with other happy couples.
I'm wondering if there are any divorce support groups you can go to?
Take heart, dear OP. This too shall pass. I think it's all part of the healing process.