May I stop paying child support because my spouse will not give me my visitation and access?

No. The law does not recognize any correlation between visitation and child support. The court can enforce its order for support or visitation as it sees fit, but as the person who has been ordered to pay child support, you are especially vulnerable since you can be sent to jail for nonpayment of child support. Your better choice is to pay the child support and file a motion to enforce your visitation rights.