ahh I think he'd be fairly ambivalent about her at first -- he's so used to people entering and exiting their lives (Toji, Toji's other girlfriends/partners/ex-wives, his business partners, etc.) that he's not really expecting her to stick around for that long. so he tries to ignore her for a while/wait it out until she leaves, too. (except she's not going to leave, and Megumi warms up to her eventually!!)