'You had someone else you had every reason'
'No, I can't blame you for runnin' to him'

'Two people together but living alone I was spreading my love too thin'

'After all of these years I'm still tryin' to shake it

Doin' much better' 
'(they say that it it just takes time)'

'Deep in the night it's an endless fight I can't get ya out of my mind'

http://www.lastfm.jp/music/Chicago/_/Hard+Habit+To+Break

I guess I thought you'd be here forever Another illusion I chose to create
You don't know what you got until it's gone And I found out just a little too late

Read more: Chicago - Hard Habit To Break Lyrics | MetroLyrics