my lawyer says this is common sense really, are you a lawyer or just some pumpkin head pretending to have any experience with any of this?
You clearly haven't asked your lawyer about this.
Unless you want custody, bringing up this part of her past simply WILL NOT impact the amount of child support you pay. On the other hand, it can backfire on you. It could paint you in a very bad light. Certainly she'd be wise to counter with accusations of you being her pimp. You cross a line, she'll cross it too.
You are clearly very bitter. You are a lawyers wet dream. Between your lawyer and your ex, there will barely be anything left for you.
You do not have the maturity to do what is right for yourself. Your bitterness is driving you to do what you can to hurt her. This is why you wouldn't give her back her bags & shoes.
Fact is - she left you, it's not nice, it happens to lots of people. So what if she said you had a small penis and couldn't last more than 2 minutes in the sack? So what if she said the new guy had a bigger dick and could go for hours? That's just smack talk, caused by your childish reaction to her leaving.
You need to get over the hurt, take a step back and do what is good for yourself. You need to forget taking shots at her. This is not the wise path. The wise path includes gritting your teeth when the cheap shot ultimately ends up hurting you more.
Still - you are a young pup and think you know everything, so you will no doubt continue to sabotage yourself.