DAE cry for an alarm that doesnt ring?

My ex used to have three alarms every single morning: 6:30, 6:45, and 7:00 so when we broke up i out the same alarms on my phone so even if we never spoke again i would wake up at the same time he did.
This morning the 6:30 alarm went off, the 7:00 one too but not the 6:45 one so i cried for a hour because he woke up 3 times today but i woke up only two time.
Why would this have happened? I was so sure i put 3 alarms and now i checked because if this happens tomorrow too i’ll cry more i can’t stand this how can I be sure to put there alarms and they will work no matter what