Moshe – it sounds like you did the right thing for you. But why generalize this? Personally I wouldn’t want a therapist who encourages me to do something against halacha. And out of context I have no idea if his “advice” was actually good or not. But who cares really because it needs to be therapeutic for you. If someone does not feel safe, trusting and understood by a therapist then they will not be able to grow from them.
My friend was married to a ger who converted to escape from himself. After his second child he started to have a relationship with a male coworker. He was distraught and went to a therapist who told him he needed to be true to himself and not forfeit himself for his wife and kids. With adequate convincing he decided to leave his wife, and life and the therapist offered to have the wife come in to break the news together. Even putting religion aside this is not the way to go. If he was frum or had regard for religion and tried to work on repairing the marriage, who is to say it would not have worked?
I am unfortunately very wary of mental health professionals and do a lot of vetting before referring, but on the other side of the coin there are a lot of people who don’t want to accept some things they are told and spin it around to others as bad advice in order to get (mis)validated and refrain from the pain of change and growth.