If you have talked to a lawyer who has said that you have no legal right to see your stepson, it's worth talking to a different lawyer. If you have not talked to a lawyer, talk to a lawyer ASAP. Specifically, a lawyer that's at least familiar with the 4-part test in the Wisconsin Supreme Court case In re H.S.H-K. that shows a parent-like relationship. Even if you cannot afford to hire one to represent you, go for a one-time consultation.

Most states recognize that it's bad for children to rip them away from people that are like parents to them, and courts will order visitation. Many state courts have adopted Wisconsin's 4-part test, or have their own, similar doctrines. And these are strong arguments, with lots of jurisprudence behind them, that are worth raising in any divorce proceeding.

I'm not a lawyer, but I was a legal assistant at a family law firm. I saw too many men convinced that the courts were biased against fathers, so they didn't even try to fight for their kids. The men who did try (even without a lawyer) generally got custody, placement, or visitation to stay connected to their kids. In one case that sticks with me, we won court-ordered placement for a man who found out that his daughter with his ex-girlfriend wasn't his biological daughter after the ex wanted to cut him out of her life, and they did a paternity test. Even though they weren't married, and he had no biological or legal connection to the child, the court recognized the parent-like relationship, and found that it was in her best interest to continue it.

I guess what I'm saying is, don't conclude that you will lose your stepson unless and until a court says so.