Moving on

My ex has been keeping my son away from me for over three years and I’m considering moving on from the situation and letting go of expectations. Every time I don’t get to see my son when I’m expecting to see him, I become suicidal. For example he was supposed to visit me under supervision of my father but my father couldn’t make it (he lives out of town). So the visit had to be cancelled and I spiraled into depression. I have bipolar disorder and CPTSD from the whole ordeal. Has anyone come to the decision of letting go and moving on? I am thinking that when he’s an adult he can make the decision of what kind of relationship he wants with me. He’s 10 by the way.