I was/am in a similar position. Married 2.5 years, a 2 yr old and one on the way. There had been pill usage that I realized had become a problem, and then found out that he had been shooting heroin for somewhere between 3 and 6 months. When I found out about the heroin, I went a little crazy. Took our son from him. I don't even really remember the conversation, it was very brief. I was beyond angry at the lies. He was not welcome in our home, and he did not try to come home. I talked to his brother and asked him that he let him stay there if my husband would take it. Spoke to his mom, who had no idea, who took him in for about 3-4 weeks while he went through an intensive outpatient 3 week program, went back to work, and then I let him come home. Today is his 3 month sober mark. It's hard to know what to do. The kids do not need to live in an environment that has drugs, no doubt about that. But if he tries to get better? If you don't want to save the marriage, don't let the family make you feel like that is wrong. I was lucky that my husband did want to be clean, and he has followed through on it so far. He also got on suboxone, which may be the only reason he has managed to stay clean. I really don't know. If your husband doesn't seem like he is invested in getting his life back, then for the kids sake, a legal separation may not be a bad idea. You can always take him back if he can get himself taken care of. But if he doesn't choose sobriety, then you need to know the kids will be safe in your care. It's hard to make the decision that children are better off without their father. There are cons to growing up in a single parent home, but if they are in a 2 parent home that is not a healthy environment, then the single parent home is better.
I wish you luck!!! Only time will show if the choices you make are right-but as long as you put the kids first, and make the best choice you can with what you have, then it will come out okay.
