Hi, you can not have a 16 month old living with someone who does drugs. That is not safe. You can't EVER leave that child alone around this man or to crawl through the home where he might find his stash of drugs. Social services will also remove a child from a home in which a person (even if not the mother) is using drugs. It's an unsafe environment for a child.
So, you have to be firm about making substantial changes in your life. This man will ALWAYS be a risk because the urge to use often never goes away for someone that has abused drugs. You'll constantly be 'watching' him and there is a good chance he'll use again.
I personally would document everything so that he can never have anything but supervised visitation of your child and leave him. Because yes, you are sitting in limbo with a man that isn't a team mate. he's like a roommate contributing some parts of rent, electric but not expenses related to his child. He's not your partner or team mate. he's about himself. he pays what it costs for HIM to live but not you or your child.
Keep him out and move on. A future where you don't have a man in it is better than living with someone you don't fully trust. and eventually you may meet someone good and decent who REALLY wants to be a family and not just needing a roof over his head and doing what they want most of the time.
good luck
I have been through a similar situation , but when I made that decision to walk away it hurted in the beginning but once I realize my strength and that my baby girl come first it felt good,never stay in a situation because of a baby cause at the end you goin to be hurt and ur going to waste time and energy that could've been spent with someone else
Since you've made this decision, I think you should 'stick to your guns'. If he's serious about getting back together, he needs to prove it first. Meaning.... No drugs, drinking, helping out the family the best way he can. I would need to see the changes, long term (not just one or two months)... Make sure they are permanent.
I can't imagine how hard it might be... But *know* that you and your son are worth it. You and your son deserve the best. Do you think that is his best?