Argh Pippo, you sound like you are fighting the good fight. Please don't drink although if you are I get it. I quit drinking 10 months ago tomorrow. I'd have to say, like you, staying away from my X was way tougher than not drinking. Yeah, weird but we are what we are.
If you can invite whatever you feel about this guy in and ask the feeling what it has to teach you. There is a poem/essay called the Guest House. It is about powerful crap emotions and how to deal with them . . . .this won't cure nor end the feeling but can take the edge off.
Please, please hang tough. Get through another day not drinking. Just. One. More. Day.