Any wives had to deal with husband's CRAZY baby mama

Ok my husband and I have been married for 5 months now and have been together for 3 years all together. He has an amazing 6 hear old son that we adore. He and his baby mama was able to be cordial through out our dating years which allowed him to have a relationship with his son. But since we've gotten married she refuses to let him to be a constant part of his son's life. She says it's MY fault. What the heck did I do besides love her child as my own? She said I have nothing to do with her son. She says anything to do with her son is between his father and her. I thought this was crazy because my husband works 12 hour shifts, so when her son was with us for the school year it was ME who got him ready for school, fed him, went to PTA meetings, school plays, did homework, Bath and bed. Why should I be EXCLUDED??? I'm a huge part of his life as well. I may not have his blood but I'm a parent too. Now I'm pregnant with our first together and she's insinuating that we are starting a NEW family with out her son and she's feeding him those lies. I would beat her up lol but they live in a completely different state. Any advice ladies because my husband misses his son and I can't help but feel semi-responsible. Sorry so long.