Boyfriend's ex-girlfriend called him

So guys I need advice about this situation that I'm in and I'm really unsure if I should say something or not. Yesterday, while laying in bed my boyfriend was on his i phone looking at clothes and I payed my head on his shoulder to join in on what he was watching.When he was finished he started to clear all the apps that are currently open and on the top of the screen you can see a list of the most recent phone calls or text messages placed for that day. It was like her name (his ex) popped out of that phone screen at me big as day,he continued to clear the open apps from his phone while I was watching and put his phone to charge and we said our I love u's and good nights to each other. However,I have been losing sleep over it because I want to know why was she is your most recent call list? Are you two back communicating with each other? And why is her number still saved in your phone after "everything" that happened and 3 years after we have been together? My question to you guys is should I say something or wait until the issue comes up again?