Child custody

[HRashid]

Hi - i was married for 15 years and have been divorced since Oct 2016. The ex and I had an arrangement between ourselves that he would see the children on a Tuesday evening for a couple of hours and on a Saturday. The timing on a Saturday was open and flexible between the ex and the children (son currently the age 15 and daughter 8years of age).
Last 2 years my son has not been interested in meeting his father yet the daughter has spent time with him on the allocated days. I have put some restrictions in place no sleep overs and of the father is to take the children to grandparents or extended family he must be present. He has never gone above or beyond for the kids and does not pay child maintenance, due to signing his 50% share of the matrimonial home over to me.

The issue is one month ago I got married and since then he has changed his attitude towards the kids. More so my son where he trying to manipulate him.
He has tried to write up an agreement for the kids but it is very open winded and not specific for the children's needs. I would rather him go to court and put a child arrangement order into place, which he is not. He is using my son and exploiting him to not stick to the routine we have in place.
Sorry for the over detail but I thought it might help put things into context.

I don't want to stop the kids completely as I don't want my kids to hate me or my son to rebel against me?
I don't agree with the agreement, how can I push him to go to court?

He has also asked for some items back which I have agreed too, but I am going through a solicitor and getting a clean break consent order in place. Could this allow him to put in a claim for the house ? Despite I own the property and my name are on the deeds?

Any advice or help would be grateful please ☹️

At 15 your DS can pretty much choose whether he sees his father or not. I can't be certain but I don't think the court would force anything upon him.

Why don't you allow him to have overnights? He can write up any agreement he likes for the DC but if it isn't ratified legally I imagine it can't be adhered to.

I did not allow sleepovers over the last two years - however over the last month during the summer holidays I have allowed sleepovers, as my sons cousins and relatives are here from his paternal side.
From allowing him to stay over on the days me and his father agreed, the father is encouraging him to stay more. My issue there is no structure or routine.

He reason I didn't not allow sleepovers as I have some stipulations regarding the company the ex keeps, and what goes on in the grandparents house, the uncle who lives there supply's drugs, I do not want my child to be exposed to that. The Aunty who also loves there (dad's, brothers wife) is the lady the ex has an affair with.

At 15 no court will push your son to stick to a routine. To be honest at that age it should be as and when he wants to go.

The routine and set dates might benefit the 8yo.

Does your ex live with his parents?

The ex does not live with the parents.
The routine and structure that we have had in place has worked for the last two years, the ex attitude has changed since I have moved on and got married (since July).