Lena and Ian are on opposite trajectories as far as finances go it seems. Lena peaks early, and has more things to spend money on in the game i.e. tattoos, sex toys, fancy dresses, sooner than Ian does. But she hasn't really gotten anything new to spend money on recently, whereas Ian has had more and more things to spend money on, while he's looking for a place of his own; even if he's in a good relationship with Perry. He's had fireworks & food expenditures for the beach house, gifts for his love interest, the MMA tournament.Keep in mind not only can Lena also be in this position much earlier in the game her expenses are also much higher.
Ian's job doesn't pay as well as Lena's services to Seymour (obviously), but Lena pretty much always has the cafe and EK has given her multiple other ways to keep making some money through music, life events, StalkFap, model work, and as a Bartender. Ian is also pretty limited in his options, if he quits his job working for Minerva he's pretty SoL unless he pulls through with his novel.
Lena can be willing to pay more money for rent, but she doesn't have to. As of now there are no repercussions for refusing, and she is guaranteed a place to live still. Ian could be in jeopardy of losing his living situation with Perry either due to financial reasons, or because he slept with Emma and pissed Perry the fuck off.