HE HAS A GIRLFRIEND!!!

i’m friends with a boy, let’s call him callum and he was dating a girl, let’s say amelia and they were dating for about a month but broke up about 6 weeks ago as it wasn’t really working and he said it was way to rushed and the feelings just kinda fizzled out. And we speak everyday but for about 4 weeks now, so 2 weeks after amelia and him broke up, and he’s been really flirty and said that he likes me and can’t wait to meet up and actually go on date and be more thanks friends etc after this corona lockdown has been lifted. It’s been going really well and i trust people very easily and that’s my down fall as i’m hurt when people break that trust. He doesn’t post much on instagram and hasn’t done since before him and amelia broke up, but he posted a picture today and uno since we’re ‘talking’ and he always comments on mine, i thought i’d comment on his but i go to his comments to see...his ‘ex’ girlfriend comment on it saying that she misses him and loves him and he’s sexy in a series of different comments. I honestly don’t know what to think, he responded to all the comments but those from her so i’m not sure what to think? whether i’m worrying for no reason because i’m honestly not the jealous type and just ignore it or bring it up to him? i just don’t want to sound moody but i don’t want to be led on