1st of all this other child is not 3? Am I right! LOL 3 year olds! OMG the things they say.

You need to call this mother and have a chat with her as she is probobly very sensative as this is new to all of you.

Call her if you already haven't and ask her to come and chat with you. Be very upfront in letting her know how she must be feeling and let her know your son didn't mean it hes just having a hard time sharing his Mom right now and thats its n adjustment period for everyone!

Let us know how it works out!

I feel for you as I know truely how you are feeling!

Hugs