I'm sorry for the end of your relationship. It sounds like it's done. Perhaps it's better and you can learn from this, have time to reflect. Now you've had some experience of parenting, you can think about this and take this into account when choosing a future partner.
I was wondering what you meant with your opening post. I thought it would be the sorts of things we do to encourage time away from gaming screens, study time, hobbies etc which some people think is too much.
I think you have massively overstepped. I am a stepmum (note not everyone who posts on this board is) and as a full time stepmum I am more involved and have a lot of say. However, I would never impose these sorts of things, particularly against their father's wishes.
Although I am curious, would you say your involvement contributed to how well Y7 and Y5 are doing academically?
In terms of the things you mentioned
This is such a drama that if they are only with you part time I would be relatively laissez-faire and leave to their father (sounds like their mother is happy rather than complain standards lower at your house/Disney Dad etc)
- oldest getting detentions/not doing homework
If in GCSE years and it's happened more than twice, we would talk to them about this in a fairly firm manner. We'd also be encouraging good study habits and introducing tutors which we've found helps. So I think he is possibly too relaxed on this.
I think 3-4 nights out of 7 is ok and I'd rather they didn't do it at weekends (partly if our help or input is wanted!). However, one of the younger DC is about to start at a senior school which encourages every night. We will keep an eye if this DC starts performing less well, may need to up their work.
Put it this way, I would ideally like all the children to be getting 7s in GCSEs across all subjects and have good emotional and social intelligence. This would be a preference over 9s in all subjects and poor EQ. Or 9s in some subjects and 5s in others.
(Obviously not all children will be able to do our ideal! We will do our best with whatever resources we have at the time)
I'm amazed she is ready to sit her GCSE English in Y7? It sounds like she could sit earlier but this doesn't mean she should be pushed in all subjects.
That's fantastic.
However, she's doing well top of her class presumably and if starting senior school as scheduled will start with confidence and hopefully thrive.
I know of two boys who started at the same local football team. One had full support from their family for the football including emotional and financial. The parents were pushy and focused. The other had some support but not anywhere near that. The first is playing professionally, the second had a few good years and has lost his way. I'm not sure it was the right career for either.