TJT... I have a stepdaughter and I just sent her a gift. I have been in her life since she was seven years old and she just turned 19. She has never lived with us but she told me her biggest worry about my H leaving was that it would damage the relationship she has with me. I think it is completely appropriate to send your SS a small gift and a card. He is not his dad. He might be wondering about you too but hasn’t contacted you because of the awkwardness of it. If he doesn’t respond or responds negatively, then whatever. More likely, however, he will be happy you remembered him and that you still care.
Good for you on using the STOP technique. The OW thing isn’t something I’ve had to deal with in my sitch. There might be one but I haven’t gone out of my way to find out. It wouldn’t change the fact that my H has moved out so I don’t need to know right now. It would be just adding more pain to an already pain-filled situation. Do your best to stop your wandering mind. The fact that she would be posting that stuff when she is seeing a married man tells me that she is an affair down. I would also recommend staying off social media until you are feeling a little more detached. I avoid it like the plague. (((TJT)))