Sooo my bf and i have known each other 5 almost 6 years

We broke up for 2 years and got back together about 6 mnths ago

There was a lot of issues with fb and whatever for ages

He added me but i was on restricted or couldnt post or tag

Since before we got together i knew he had an old fb he used when we first met but he said it was deactivated-i tried using mutual friends or someone not mutuals fb to find his old fb as i suspected he was using it still to talk to girls as obviously that fb wouldnt have him listed as in a relationship but i never was able to find his old fb.

Anyways a few days ago his sons mums dog and his dog got out of the yard (shes dog sitting as his house goes up for sale next week) she put a post up and his old fb profile was tagged in it 😑 when i go onto her profile i seen his dad, mum, sis etc are tagged in photos of their son aswell as bf old fb. Wth so idk what the hell to think now?? He sworn to me that it doesnt exist but i know he can log in and redeactivate in seconds anyways.

Im really second guessing his loyalty and what to believe anymore ive had this horrible feeling in my stomach about him lying for a while now.

Any advice would be great :( makes me so disappointed