Can I stop making child support payments if my ex refuses to honor my visitation rights?
No, you cannot. Child custody and child support are not related in the eyes of the law, so attempting to withhold one in an effort to enforce the other is not allowed. A child support agreement is generally worked out as part of a divorce settlement, or determined by court order. Even if your ex-spouse refuses to honor your visitation rights, you will still need to continue making child support payments as per what was ordered by the court.
Failure to make timely payments could result in you being charged with contempt of court, facing legal action for breach of contract, and ultimately having your wages garnished and other legal and financial problems. Unless life circumstances have made it necessary to seek a modification of the original child support agreement, you must continue to pay on time and in full.