quick - try and remember something you did before you were in 2nd grade. How many memories do you have?
Your kid is what, 3? You keep missing the point, the ex has you wired tight and you fall into the trap every time. You believe this women, who cheated on you and then remarried quickly, but now she is going to be honest and up front?
You really can't let it go, you need to get into therapy and put in the work. You are your own worst enemy. You have what you wanted, a quick divorce and yet you constantly try and talk things out like you are spouses. If she schedules something on her time, it is none of your business. Unless it is something you can show up publically too, like sports events or school events, get over yourself. You are trying to insert yourself back into her life and using the kid as a pawn is what it looks like to me.
Fix yourself, otherwise you will be doing the same thing expecting different results. You have been told over and over and over. Noticed how proud of yourself you were that you thought you "got over" on her? GROW UP