I can feel myself slippin\'

It almost a week since the last episode and I can already feel myself slipping back into the relaxed mode.  Why does that happen?  Why do I begin to forget who I'm living with?  I'm most certain that this is the reason I've been in this relationship for so long.  Its like a circle...The Beginning is the calm.....The Middle is tension rising.....The end is the big ass fights....Then it's back to the quiet again.  Now that I think about it.  I won't have to remember because this is the beginning of the circle...the quiet.  But how do I NOT fall back into the comfort zone without starting trouble.  I just want to be cordial and fair.  It's useless to try and talk about it because I already know whatever I say he'll just answer me with what I did or I made him do it (also know at it's my fault) I'm still going. I just need to understand some ways to protect myself from falling back while I'm here.  Any suggestions?