pinched by a jealous crab

i know this cancer guy from work, we have known each other for almost four years. all this while, i have developed major feelings for him. i confessed once but he hasnt said anything, and that was almost two years back. he has never said he likes me or wants me to be his girlfriend. i know cancers dont like to be pushed so i never asked him, only patiently waiting for him to get out of his shell and say what he feels when hes ready.

in fact, he has a lot of female friends and flirts with them. however, he flirts with everyone but me and gets insanely jealous even when i talk to another guy about work. like he would just literally stand from his cubicle just to stare at me or more like watching over me to see if i was flirting or not. lol

he's a sweet guy but he seems to make up his mind and seems like he's taking his own sweet time, which is fine but he gets all stirred up and almost crazy when he sees me talking to another guy. it makes me wonder if its normal for cancers to want someone so much and keep it bottled inside and wait for the other person tk pursue? but ive read some posts saying cancer guys like to take the lead.. which is why i havent initiated anything, fearing he would retreat in his shell, and that would make me miss him terribly.

my sun sign is leo, so im okay with him being jealous and possesive but kinda confused why he tortures himself feeling all that and yet still hasnt said anything about he feels for me. what do i do?