Does facebook link different facebook account activity if using same wifi and use to show same ads to the account using same wifi?

I logged into my bf’s facebook from my wifi. Everytime i log into his fb it shows me engagement rings.

I have liked engagaement rings on my own fb so is it showing rings due to my fb liked pages and using the same wifi orncould it be this is what hes searching for on his phone? We dont live togethet btw

ads facebook link privacy wifi