Telling Berna she's free to choose which club to join is the right thing, but of course it's plain obvious she'll still join him. Because she likes him, and less about her not exercising her freedom. I'm expecting a crowd of jealous guys giving him the stink eye for having two cute girls living with him.
I'm just a little surprised he can deal with pushy gyarus so well. Not even that black-haired shiro gyaru sitting on his desk could fluster him, in other manga with typical weak male leads, he would've been as red as a tomato and unable to speak coherently from that alone.