So when does the next girl get introduced? Harem is directly in the title. Now that he has a house, it would be a good time to build one. Some to bring into the dungeon, and one you leave behind for full time housework. I don't think you can expect Roxanne to keep up with everything unless you are cutting down dungeon time considerably. Plus more girls = more girls and that's reason enough for a harem man.
But I suppose he probably needs to go earn money first since he just spent a whole bunch.