Hi Amelia,
He was fully aware that he was married when he met you online and started dating you virtually for the last 3 months. He was misleading you on purpose. That is never a good characteristic in a person.
If you were to keep him in your life as a friend with the intent of only talking to him casually, at some point in time, you could easily be misled into thinking that you should start dating him again.
It was this easy for him to mislead you for 3 months, who’s to say that he wouldn’t find a way to make you believe that he has divorced his wife and wants you to give him another chance at dating?
The point here is, he cannot be trusted. Stay away from married men online. They can make you believe whatever they think you want to hear just so that they can keep you around. They will communicate with you for sustained periods of time until you become so emotionally attached to them that you just can’t let go, even when you know you should.
Friendships come about through honesty. Trust is not only important in romantic relationships but friendships as well. Given how your relationship with this married man began, with lies and dishonesty about his relationship status, he would not be a good person to keep as a friend. He can’t be trusted. You should block him entirely and move forward with your life.