Anon
don worry alrights. first thing, we tend to misconstrue and misintepret things around us. just saying another girl is hot doesnt mean more than just shes good looking, which is just a harmless opinion. any intepretation beyond this point, such as "those he'd like to sleep with", are just speculative, so dont delve into that. even if he doesnt say it out aloud, it will still not change his opinion and thoughts deep down. hes still gona think that the girls is hot, wihout saying it.
"there's a difference to who a guy thinks is hot and who he actually wants to be with."
msb nails it. theres tons of hot people in the world around us.if everyone were to leave his/her partner for the next hot girl/guy, then this world would be a mess. its perfectly normal to find another girl hot, its intuitive for a guy to notice and comment on a good looking girl. but i will hesitate to equip this with love or anything like that.
the only issue might be that it makes you uncomfortable. so i might suggest that perhaps you talk to him about it.