In love with a man who lied to me about being single. He has had arranged Muslim nikah,?

So I've been dating this guy, everything seemed to be going well and then I started to feel like something wasn't right. The other day he was on the phone to me and put me on hold but must if thought he had taken it off hold and ended the convo but I over heard him chatting to a woman about moving in together this week ect. As you can imagine I got pissed off an let him know I know. At first he tried to deny and then explained that the woman is in love with someone else and it was a arranged Muslim nikah they had but nothing is legal and they are trying to show their families that it won't work. He is asked me to give him a chance to make them realise because he wants me but o don't know what to think. I don't know if I can believe and trust him. And what of it doesmt work and they end up married legally! I'm so confused