When a guy who dumped u walk past u nd u ignore him every time-so when he once walked past u nd u ignored him then he sighed loudly while walking past u-what does he mean by that?

this seems difficult. but as i can see that this boy is fed up. he clearly misses you. and wants to be back with you, and i think he regreted dumping you , maybe you should talk to him and see what he has to say.