Should i wait longer or ?

Sorry I posted other one in the wrong category.....Ive been seeing this guy for about a month and I really dig him. I've met his family and his friend and he has met mine. What is bothering me though is he has still not told his ex that me and him are seeing each other. I've asked him about it before but he says he doesn't want to open that van of worms yet. Now mind you the ex is a bit in the obsessive side. She blows his phone up 24/7 and he is always sending her to his voicemail. he gets pissed about it. He has told her not to call like that but she don't listen. Keep in mind too she ran off ten months ago leaving him and their son .my question is how long should I wait for him to tell her about me. I don't want to give up on the relationship just yet cause I know he really likes me he just has to deal with her. I was pretty bad with my ex too but I eventually stopped being that way because he moved on then I did.