This is a slightly-venting-yet-realistic question, but...
What if you actually LIKED who you were before your spouses affair, and you miss that person? I wasn't vain, it's not like that, but I was happy... with myself, with my children, with the person I thought he was, with God... you name it, I LOVED it. Now, well, most days I'm either walking around numb or wishing I was.
I will truly never be the same. I suffer CPTSD, and that's permanent. Treatable, but permanent. Who knew you could love so hard that the shock of it all crashing could almost fry your brain? It's tragic. Not ALL change is good.
The crazy part is, to many people in my shoes, my situation may be the 'ideal ' for hope! Upon discovery, my non-Christian husband (I'm a Christian) repented, gave his life to God , sought men's counseling (til the funds ran out), owned his faults (if not somewhat distorted), gave up his life of sex addiction, and proclaims his love for me daily. Me? I'm fighting through a jungle of vine-like distorted thoughts, constant triggers, self loathing, suicidal thoughts (occasionally ), disassociation, hyper vigilance, eating disorders, and the list goes on and on. The kicker? We're 20 months out, and that last sentence describes the more stable me (I've stopped hallucinating, fortunately without medication).

I miss myself. Sadly, I remember the former me. I remember who I was when I was full of adventure, hope, and creativity. And love. I wasn't perfect, far from it actually, and I've never been in denial of that. But I lived content, except in my marriage. Still, I loved him utterly.
No, I wasn't always this cynical (I miss optimism). Yes, I STILL believe in God, and I cling to faith (when I can think). But I MISS myself, the dreams I had, and the marriage I thought we would have.

I agree, change in life is inevitable. Good or bad, right or wrong, it's coming. Grief is a part of life. Just like joy, however fleeting.
How do you grieve when you feel like you've lost every good thing, only to gain what you never wanted?