Why did my boyfriend cry?

when i told my boyfriend that i might break up with him and would cut all contacts with him thereafter, he cried really hard. his ex had cheated on him before their 3 yr relationship ended. im his second gf and we have been together for 3 yrs and 4 months now. i've never seen him cry in these 3 years, was he just acting or did his crying really mean something? he was hugging me and rocking a little while he cried his eyes out. the strange thing is he was okay when i said we should break up but then teared up when i said that i will cut all communications with him afterward. he said even if we do break up one day, he still wants to be friends. i told him that was impossible, and then he started to cry. strange, no?