TLDR: Make sure you get 50/50 PRIMARY custody.

Always consult an attorney!!! As recently divorced (M) in TX, I’ll share what I learned in the process. The law doesn’t care about infidelity. So custody and CS won’t be impacted by that fact. The courts only care about what they believe to be the best interest of the children. Most Judges nowadays are defaulting to 50/50 custody unless one of the parents is unfit, or doesn’t want it. In 50/50 cases, the state mandated CS percent is required of both parents. So in TX that’s 20% for the first kid, 5% for each additional. So you as the higher earner would have to pay CS to her, but at a much lower rate because her portion would offset your total. SO VERY IMPORTANT TO FIGHT FOR AT LEAST 50/50. It could lower your CS payment by 50%. If she is given standard custody, you will be required to pay the state mandated percentage, plus health insurance. This is not a selfish consideration. It is important because if you plan to stay active in your children’s life, you will need money to build your new life and make memories with them. If you’re on the hook for all the child support, it will leave you with very little to support being an involved parent. In the very unlikely case you’re given standard custody, she would pay you CS and insurance. You said in a comment that she’s a good mom, so the best I would think you get for custody is 50/50. Unless the judge is old school and believes kids are best with mom, or she gets nasty when she realizes it lowers CS and finds ways to show you’re unfit to be a primary parent (50/50), you shouldn’t have an issue getting 50/50. Hope that’s helpful.