How to do I tell my son I am dating someone after divorce?

Hey there. I am so sorry to read that you are in a situation where your child is being told horrible things about you by your ex. No child deserves to hear that the parent they love is a "whore." That's not fair to them and really can be traumatizing emotionally. In regards to your question about when to let your son know that you are dating, I would recommend to go ahead and do it. Your son probably already knows (kids are so smart and intuitive!) and by you telling him this will validate the experience he is already having and probably answer some questions that he has.

The depth in which you speak to your son about your dating situation really depends on his age. As a rule of thumb, less is more when they are younger and as they mature you can add more detail if you see fit. Children have so much to worry about, you don't want to add any extra "adult stuff" that they are not cognitively able to handle. When we "overshare" with our children they often will feel responsible for things that they have zero control over or they tend to misplace blame (and often on themselves). 

I would definitely recommend that you continue being emotionally responsible by not bad talking about your ex to your son. I know that can be hard to do but it will pay off for your child's emotional development in the end. You'll be grateful that you said kind things (or nothing at all) over anger and resentment as he will feel safe when he's with you. I know these situations can be so very difficult to navigate as emotions tend to run high. Try your very best to keep healthy emotional boundaries with your son and only give him information that he is developmentally prepared to hear.

If you have more questions about that, get in touch with a therapist who can help guide you. They will know developmental stages that your child is going through and what information is appropriate to say and what is not.

Hope this helps! Best of luck to you!