Ah @Icantdothistoday I really feel for you but I don't have any words of wisdom because I'm in a very similar situation. I'm older than you and my particular situation has been ongoing for nearly 7 years. That's 7 years of my life I've wasted.
Over the years, I've blocked him many times but he just gets another phone and round we go again.
Every time he gets back in touch I hope that this time it will be different - but it never is.
Every time he gets back in touch I'm so happy and relieved.
Every time he gets back in touch he ends it and then I'm miserable and spend my days surgically attached to my phone, hoping desperately for contact.
Every time after he's ended it, I reach a point where I block him and I do feel relief - right up until the point where I don't feel relief any more and long for him to be in touch.
But - he ended it again ten days ago and this time I blocked him immediately. And this time I genuinely don't want him to be in touch any more. I don't know why I feel this way but my god I hope I stay feeling like this.
Don't be me @Icantdothistoday, don't waste your precious time. I'm closer to 60 than 50 now and just feel like I've let myself down and squandered so much time. You can be strong, believe in yourself, treat yourself with the love and respect that he hasn't treated you with, and that you deserve.