It sounds like you and your ex are co-parenting... if that's the case, you might want to reconsider before telling your child about the nasty details of the affair. It's likely to make effective co-parenting even tougher to make happen. I can't imagine how much it hurts to think of your child spending time with someone who is so closely associated with the end of your relationship. But don't forget that it was your ex who broke his commitment to you and to your family - talking about what 'kind of person' his current girlfriend is would be tough to do without including what 'kind of person' your ex is.... and while he might have been an awful partner, trash-talking your child's other parent rarely ends well.

This is a really tough situation. Many hugs.

Thanks, good advice. I'm a bit blinded right now by how intensly I dislike this woman (theres a much bigger story here that I won't get into, lets just say she is a predator). My gut was kind telling me that, I guess I just needed to hear it from somone else. Thanks for being the voice of reason.

i would say NO.. i would keep the kids out of it and i know thats hard to do. whats happened between you and your ex happened and you will think that the 13 yr old will see it for themselves.

I also agree with not bringing it up with your child. It took me a while to realize, but children have just as tough of a time dealing with divorce and adding any further stress for them is not helpful. In my case my children discovered on their own and I think it hurt me more that they knew than them. Hard to explain that type of behavior to children.

There are some things we don't need to know about our parents. In addition, you need to be careful how you communicate with your child about the other parent. As a kid who was made to feel guilty about having a relationship with my dad (who had affairs) I feel pretty strongly about this. My sisters and I always felt very torn because of the comments our mom made about our dad and his new gf who he ended up being with until he died...that was about 30 years. Kids should never, ever be made to feel bad about something the other parent did. That's not their issue.
I'm really sorry your family is going through this and I know it's very hard. Kids often figure these things out for themselves over time. 13 is a tough age anyway with everything they have going on and it's hard enough when parents split up. I understand that you want to hurt your ex as much as they hurt you and that's natural. But you clearly have your child's best interest at heart if you're questioning telling him rather than just going ahead and do it. That's a wonderful thing. Be supportive and positive...that's what your child needs from you. Hugs!

Good advice all and I will follow it. Just sucks that my son will have to spend time with someone's whose morals are so despicable.

I don't think the children need to know about affairs. My kids were 10 and 8, and while I wanted to destroy the image they had of their saintly father, it isn't for a child to know.

I might consider telling them if they were older, closer to 18.

Are you raising your 13 old to be an adult?

If so, it is my opinion that you give him the support and skill set to deal with reality and truth both pleasant and unpleasant.

Hide the truth in order to protect only protects the guilty, if a child needs protection from a parents truth...

My parents divorced when I was 13. My siblings and I knew dad was having an affair. Mom didn't need to tell us.

I think your son probably knows a lot more than you think.