How long have you been dating him?
Did you know he was married?
What is your question?
Have you spoken to him about the call? If so what was his response?
Is he still living with her?
thank you for that additional info. I would certainly call him and let him know that she called you. The question would be how she was able to get your number off of his phone to begin with. The may not be living together, but she obviously got close enough to him to be able to go through his phone, which is concerning. Let him know that you don't appreciate her calling you or getting your number and that you don't want t happening again.
If you're worried about her taking you to court, she has no grounds to do anything to you. In fact, if she continues to call you, you can let her know that you will file a restraining order on her if she doesn't stop. You may want to consider not seeing him until he takes care of things, but if you want to keep seeing him, that is totally a personal decision.
I welcome your thoughts, let me know if you want to talk more