Why is my ex behaving so wierd?

So i broke up with my boyfriend year back as he cheated on me.He cried till he puked to get me back and did try to convince me but i was on my stand as i felt i deserve respect and a better person. But now all his friends forced me to talk to him as he was wasting his life boozing.But i later found out that he was dating the same girl he cheated on me with and was just breaking contacts with all people who he knew before who were in his past life.He seems to be running from everyone and me too to not answer any questions. When i asked him why he was doin so,he said because he feels guilty for what he did and couldn't face me. So my question is .. if he knew he cheated n was wrong then why is he still with that whore and wasting life ? Is he just lieing to me again or he really means it ?