Hi. Oh, please do not let your wife or you beat yourselves up. There isn't a known cause of adhd. My son has sensory integration disorder which is like adhd (they are both neurological and can look similar, some kids have both) and I have things I wonder . . . did *I* cause this? They don't know exactly what causes it and we're all doing the best we can.
Impulsive behavior is an issue with many ADHD kids. Also with sensory kids like my son. However, my son responds to firm rules. No touching other people's things did work for my son to keep his hands off. I know you are trying to be nice, but firm rules with consequences that are reasonable help. Praise anything good he does as well so he likes that. I will tell you that I had a friend's son who was always considered adhd turn out to be on the autistic spectrum when they took him to our local Children's Hospital for a full psych evaluation. He was a freshman in high school and had started a fire in the bathroom. Ya, it got that bad. Since getting the correct treatment through the children's hospital, he's on track. I'm not saying that is what is going on with your son but that you should do a FULL psychiatric evaluation to determine the best things to support him. We have Children's Hospitals in the US. Do they have that where you are?
What type of medication is he taking, what dose and for how long has he been on it?
Specialmom is correct, there is no known link to having adhd and what your wife did.
You also need to recognize that the adhd meds have a very specific time frame. They may not be lasting long enough for your child. Let me know what he is taking and I can tell you how long they should last if he is appropriately dosed. But, this is important, a psyc always starts with a low dose and waits for parents to tell him how it is going. Make sure you communicate to him what is going on!
I have lots of resources on working with adhd kids. This is a good starting point. Stay in touch
Is there any update with your son? Hope all is well.