Matt gave some good advice!
Also, There’s the hurt (that you won’t admit in front of her) and then there’s the hurt from her thinking you can’t handle the truth (which is shame, but you experience the emotion as anger). In her defense, as a woman, I wouldn’t want my ex to know about any new boyfriends ~ I’d love them enough not to want them to experience hurt. On the flip side, some women won’t do this and then the two guys get jealous. Because her keeping him a secret means that she really likes this guy AND really cares for your feelings ~ it’s over, or she would (subconsciously) triangulate you (by not saying anything to the kids).
Clearly, she is “wrong” for choosing a new boyfriend right off the bat. I agree with you there. But, that’s just our opinion, and it’s a free country. There is nothing written down by God about a set mourning period after the end of a relationship.
You could also tell the kids not to tell mommy about daddy’s new girlfriend one day because she can’t handle it. But kids (and most people) instinctively know the truth, who the weak ones are, what the deal is. So don’t worry about looking “weak” in front of the children.
Though I run this site, it is not mine. It's ours. It's not about me. It's about us. Your stories and your wisdom are just as meaningful as mine. 