Husband tried to cheat

So my husband tried to cheat on me. He didn’t say that to me until I confronted him. He broke his phone during our fight and got a new mobile which is dual sim. So I suspect about this too. I don’t trust him now and I want to listen to his conversations with other girls. How to I do this ladies?

Update: I have a 7 month old son. I dnt to make it hard on him. He tried to cheat once he says he is regretting it. But I still dnt trust him. Only way To check if I can trust him again is to see how he is behaving when I am not around during his calls.