Put yourself in his shoes people!
Hes "Been" with noirin for a long time now, and these people just walk in and start talking to all the originals and making themselfs at home..
I know I would be pissed if my girl started talking to lads like Tom who she just met, and you could see on LF That she was sorta ignoren marcus too lol
But then again she isnt really his Girlfriend at all so I guess he has no controlle over her