I've been divorced more than 10 years. Usually if ds has something hes doing at school, we swap weekends so that access isn't cancelled (all contact court ordered years ago) which normally runs smoothly. Ds has rehearsal for something and it happens that the rehearsal is on exes weekend. Out of the blue hes contacted school directly to say ds not going without even bothering to swap etc.
Last month he suddenly rang school to say ds wouldn't be doing an open evening (which they just told him was compulsory) without any attempt to sort something out. At 13, ds has things going on that mean juggling times sometimes (not excessively, maybe twice in a 6 week period say) Why would he suddenly be cancelling things with school?