Grounds for Breach of Marital Separation Agreement

My ex an I have been divorced for 1.5 years. I am remarried. For the past 2 years I have taken the boys on trips that involved leaving on her weekend. We have joint custody and they spend a week with me and then a week with her. She has recently informed me that I cannot take them on her nights this year. Not due to a conflict as I have clearly presented a calendar and given up one of my weekends in exchange, but because she is mad at me. This is clearly a breach of our contract, but do I have enough to take her to court with this. I pay about twice what the court ordered child support would be, and did this freely to make sure a good roof was over my childrens head. I have other factors, but I am not sure they constitute material breach where I have been impacted monetarily. What other grounds would I need to take her to court seeking the ability to work with the calendar and reduce child support? One other point is that she did not have a job when we started, but she now does have a job.

If the summer vacation provision allows you to take the children during one of your ex’s weekends and she is refusing, she is in breach of the contract and you may pursue an action for breach against her. If she is found to be in breach, and your agreement provides for an award of attorney’s fees to the prevailing party she will have to reimburse you for your attorney’s fees.
If child support and child custody are contained in a separation agreement you may file a motion to have the court determine custody and child support at any time.