My (23F) boyfriend's (30M) ex gf facetimed him at 10pm. He says they don't talk often, but I'm doubting it.

i'm 23f, he's 30m. they were together for 9 years and only broke up last year. they share a phone bill / insurance stuff and are on good terms.

he missed a call earlier and we were already in bed, he'd left his phone in the living room and didn't wanna get up to answer it. an hour later, i went to the bathroom and he asked me to get his phone. when i picked it up i saw that he missed a facetime from his ex. i mentioned it immediately and he didn't react much, just said "oh.. that's weird." he claims they don't talk that much.

now i'm on the couch and i just heard a notif that someone "loved" his message and texted back. i'm spiraling so bad rn.

i want to discuss it more tomorrow. i don't wanna seem controlling but i think it's reasonable to want him to limit contact with her. i don't wanna feel stupid if he's being sneaky.

so, how do i go about bringing up my feelings to him?