I wish I could disappear

Aiko - sometimes you need to let them 'have it out'... some people tend to argue as a way of communications - it's better to communicate than not at all.  What if you asked them to sit down and talk about it?  Maybe a group therapy session would help?  My father and I were that way all the time, but now we're fine...  Maybe tell them you are not the referee.  Also try something to break the pattern - if it's like that everynight then try to switch it up on them somehow... go watch a baseball game somewhere and get out of the house.