Thank you everyone for your comments. But I forgot to mention one important thing. She would probably leave with my child.... Something I can't even imagine..
Well, she can't simply leave with the child without a court order - if she does it's considered kindnapping - even if she's the child's mother.
Does this ring a bell?
The mother of this guy's child (who just like your kid was born in the US) went home to Brasil with their kid. She was supposed to be there for 2 weeks to visit her family. Instead she never returned, started dating a prominent Brazilian lawyer and blackmailed her husband into granting her a divorce "so he could see his son more often." When he signed the papers - she kept withholding the kid from him anyways.
Well, then all of a sudden she died giving birth to the child she had with her new husband (karma?). Shockingly and against all children conventions Brazil had signed in the past - the Brazilian courts then granted her "new" husband full custody of the child (remember he is a prominent lawyer in Brasil). It took many years but the boy is finally with the biological father.
From what I've heard Poland is a stickler to most if not all UN conventions regarding child custody which means if your wife simply took the girl home without a court order you'd have a very strong case and she'd probably lose the custody because of the "kidnapping" charge.
A shared custody is a must as children need both parents - unless extreme reasons exist (violence, drugs, alcoholism, etc, etc.)
Hope this never gets to that point and that y'all work things out.