Good Day

Me and my ex wife got seperated during May 2019 and finally divorced in Feb 2023. Since May 2019 we lived in seperate houses and shared custody of our 2 children. They are two boys, aged 15 and 13 currently. In the almost three years of seperation the agreement was that they spend one week with me and one week with her. Due to proximimity to schools it made more sense that they often stayed with me for longer periods of time, sometimes up to three months. I had no problem with this as I want my children with me as much as possible.

According to the divorce papers, we have joint custody, my ex wife is primary caregiver, but there is no clear guidelines as to where the children "must" live. Costs of the children are simply split in half in terms of school fees, medical expenses etc. There is no maintenance payable to any party as we share custody. On abnormal or big expenses, we have a discussion as to who is responsible for the expense. there has not been major issues around expenses for the children. 

One of the major issues me and my ex wife had was our different views on raising our children. I am much stricter than her and I believe in setting clear boundries. My ex wife is the exact opposite. Boundries, discipline etc is not important. 

In July 2023 my ex-wife's parents moved into her house and she moved out to go and live with her then boyfriend, now fiance. There is no room for our children in his house and when the children are ander her care, they stay with her parents.

My youngest son is boarding school (by choice). We see him every second weekend.

The problem is with my oldest son. He alternated between me and his mom's house on a weekly basis (give or take). I suspect he was not aware of his mom not living in her house anymore and shorly after dropping him off there in July he called me to come and collect him agaim. I could see he was upset, but he did not want to discuss it. He then lived with me up to the end of September 2023. Me and my partner had to attend a wedding in Gauteng and we asked him to spend the weekend at his "mom's house". At that point in time he had lived with us for three months without visiting his mother. He agreed, but was not very happy about the situation.

I suspect he was manipuled and we were badmouted. He now refuses to live with me and my partner as I am too "strict". The problem is that he has given up all his activities at school and his marks have dropped significantly to the point wher he failed two subjects in the first term of this year. His words: "I did not study enough" His mom: "No you did, it is the teachers's fault" In her eyes they can do absolutely nothing wrong and anyone that dares to disagree with her is attacked. 

His mom does not stay in the same house as him and he comes and goes as he pleases. If his grandparents try to get involved, they are told to not interfere with his upbringing.

If I say anything, I am told that I am not the primary caregiver, she is and I have no say. If I dare repremand him, I get repremanded infront of him.

My questions: Is it acceptable for a parent that has custody to go and live with her new partner and leave the children in her parents' care?