May I stop paying child support because my ex-spouse will not give me my parent-time and access?

No, you can’t. The law does not recognize any correlation between visitation and child support. You must pay your support even if you are not getting access to your children. If you have an order that grants you parent-time with your children but your spouse is preventing that parent-time, you should file a motion with the court to enforce your parent-time. Your ex-spouse can be charged with custodial interference for preventing your parent-time.