I’m new to Medium, too, so with you on responding. But so far (excepting a few people), I have found it incredible to connect with people who have been on both sides of infidelity, either as the one who cheated or who was cheated on. The commonality is that there is pain all around. I don’t know if it’s cold comfort, but usually (or often), the one who cheated gets their comeuppance in due time.
As if this year hadn’t been bad enough, what a year you’ve had! Yes, therapy is an invaluable lifelong. I’m so glad for you that you are, as you write, finding that “spark, long buried under decades of selflessness.” And you are writing, and a writer. I hope you keep writing and keep feeding that spark until it burns away everything that keeps you from being your best self.