@saine is always a click or two ahead of us
When teams retire or split after the first competition of the season (hello Marly) I often think it's either one of two things
1) Commitment level of one of the partners not matching the other
2) Realizing that they don't want to compete/train at the highest level anymore and it's better to end things before the real season starts and too much work has been done to back out.
I find that it also often happens years around the Olympic year... for obvious reasons. Teams of that level are not going to make a statement at the Olympics (or even qualify) and if that was a goal for them, they would be in for another 5 years.