Hello and welcome to EmpowHer,
In order to stay in a healthy relationship with a man with ADHD and autism I suggest that you learn as much as you can about both conditions. By doing so, you can understand him better and hopefully prevent situations where inappropriate behavior over-rides affectionate feelings.
Below are a couple links to articles that you may find helpful:
Tips for Being in a Relationship With a Man Who Has Asperger's or Autism
Adults Can Have ADHD Too
I hope that helps a little bit.