Doctor's Secret

I'm in an open relationship and yesterday I had a session with a patient where things got intense. She was complaining about her chronic pain, but during our session, as we discussed the options, she began to touch me inappropriately under my coat. I let it happen, even though I shouldn't have, she felt my erection through my pants while I talked, and then pressed against me. Is this normal? Am I a terrible doctor for letting it slide like that?