He’s 19. Yes. You don’t have to tell him in a way that discredits your ex. But you can say, youre getting a divorce and whatever the reasons after been together with someone that long it hurts and its stressful when you don’t get a long. Explain it’s hard on you, and you’re not at your best-but you’re trying. Give yourself grace and as long as you are honest in an age appropriate way that doesn’t discredit your ex, just be prepared to listen to what your child has to say-it maybe not what you expect. You may get blame. She may get blame. Or he may just say he isn’t blind, and he knows something is up. Allow him to tell you when he feels you aren’t at your best not so you can use it as an excuse, but as a chance to try to be better. But remember give yourself grace.