B,

I guess I'm confused as to why she is threatening you. What does she want? I would make it crystal fuching clear you are not budging on 50/50 and if she wants to go to court and waste thousands of dollars that have at it.

This isn't the 1950s. Courts understand that children especially boys need a father figure in their lives.

I read once that 90% of males in jail had little to no father figure.

Also, if you have to drop a little hint that you know what she's hiding from you (because she is) and you will do everything in your power to get 50/50 custody.