If I just got custody of my 2 children from my ex-wife but I pay child support on another child, would this lower my child support on that other child?

You had a third part to your question.  In Texas, visitation is not contingent upon the payment of child support.  You can actually file a combo motion.  In the same motion to reduce or adjust your child support obligation, also file a motion to enforce your visitation rights.  If she has systematically been denying you visits, some courts will award make-up visitation time.  This would be a great opportunity for all of your children to get to know each other better.  Texas also has a penal offense called "interference with child custody."  This includes when one parent keeps a child when they know it is the visitation period for the othe parent.  It is a felony level offense.   To file this charge, you will have to make attempts to excercise your visitation at the times set out in your order.  If she continues to refuse, then you can file a complaint with your local law enforcement agency.

It is my understanding that in the state of Texas child support is calculated by adjusting the gross income of the non custodial parent to a net income amount.  On that net income there is a percentage that must be paid per child.  A calculation of net income begins with the parent's gross income, which includes salary, commissions, overtime pay, tips, bonuses, interest, dividends, rental income, royalty income, trust income, retirement income, disability income, and any other source of funds. It even includes prizes, gifts, and alimony from a previous marriage. It’s best to calculate gross income as an annual figure. Once the figure for gross income is set, subtract the following (also computed annually):

• Social Security taxes or, if the paying parent doesn’t pay Social Security taxes, any mandatory retirement plan contributions
• federal income tax (based on the tax rate for a single person claiming one exemption)
• union dues
• health insurance premiums and other medical expenses for the child(ren) if the court ordered the paying parent to pay these expenses.

Then you multipy the net income by the number of children you have to support.  Here you have to pay on one but your ex will have to pay on two.  The court 's calculations depend on  lot so I would speak with an attorney in the area about balancing the matter here.  Good luck.

Under the laws of all states in this coutnry the net monthly income of each parent of a minor child or children are considered by the court based upon county guidelines of where the child support matter is venued. As such, the fact that you have custody of two (2) of your three (3) children should entitle you to seek child support from your "ex" with respect to them even though you are paying the "ex" child support on the one.