Can I terminate my ex-spouse's visitation if he or she doesn't pay child support?

Unfortunately, you are not able to terminate visitation if your child support is not being paid. If you are under a court order that provides the other parent with timeshare, it's of utmost importance that you follow that parenting plan and abide by that court order. What I would recommend is that you seek the advice and counsel of an experienced family law attorney, and that attorney would be able to recommend ways that you can enforce the child support order and ensure that payments are being made.