Not me, but my Mother indeed turned her life in a completely different direction in her 40's. Up until then, she was married to a verbally abusive narcissist for 20 years (my father–a decent man and excellent surgeon, but with unaddressed mental health issues). She and my Dad divorced at 40, and she returned to school to get the degree she always wanted. She completed PhD in English Literature and, for the last 20+ years, has been an accomplished English professor and author–writing everything from illustrated children's stories to graduate-level textbooks. She also met another man, and they've now been married longer than she and my father.

Your perspective is out of calibration. You're halfway through your life (ish). Your best days could easily be ahead of you. You need a therapist, and they are available online. Doesn't have to be one in your town. My wife and I have seen a couple's therapist online for 3+ years now, and it's an excellent way to spend our time and money.

Life is hard. It was hard then and it will be hard now, but you can do the things you want. And the second half is coming whether you do them or not, so you may as well get started.