YTA for telling him about your dissatisfaction with your wife but not for telling him to think critically about his relationship. My mom told me details about a period were her and my dad almost got divorced before I was born and honestly it really changed my perception of their relationship and hurt me. On the high school sweetheart thing, my mom encouraged me to stay together with my high school boyfriend even after I got to college, realized how jealous and controlling he was, and broke up with him. She wanted me to take him on a date when I was home for thanksgiving! The moral of the story is to just respect what your son decides, he’ll probably figure it out when he gets to college.