Piper, I'm so sorry it has come to this. I second everything Anvil said, she's is right on the money here.
Sometimes relationships can be fixed, sometimes there is hope. Sometimes a person will reach out for recovery etc
That is absolutely not the case here.
He is in active addiction. He is lying to save himself. He is cheating.
You need to go with what you know and what you know 100% is that he is a liar. He will lie right to your face without blinking an eye. You cannot trust him for one minute.
I don't know if you live together but if you do you might want to ensure you know where your money is at all times. If you have any shared bank accounts etc you might want to shut that down right now and split the funds so he can't drain the account.
You should probably also go see a doctor to check for STDs.
I'm sure it's all a terrible shock.
I have rarely said this here at SR, but the further you get away from him and the sooner you do the better off you will be.