My ex hasn't let me see or talk to my two boys in 5 years the first 2 years I tried everything but he always had some excuse I talked to attorneys but still didn't accomplish much but once a year I try and get in touch with them last year I called he said they've been adopted by his wife. I was devastated but when I started reading some of your answers that it could be possible I just have to know if he could do such a thing without my consent and how would I find this information?
The children can't be adopted by someone else unless you have relinquished your parental rights or the court has extinguished them (which involves a legal process; it wouldn't happen without your knowledge). If you are sure you have not done so, then they have not been adopted.
I would urge you to get help from a family law attorney to get a parenting pla in place, or if there is one already, to get it enforced. If you cannot afford a family law attorney to represent you, many will provide "unbundled services" (provide guidance to you while you represent yourself) and there are also many clinics that will help you.