I wonder how many romances (heart options) each character can juggle, and for how long? Ian not with Lena seems to have a good amount, iirc, with Cindy, Cherry, Minerva, Jessica, and maybe Alison and Holly. But a late Alison and slutty Holly. (Holly really gave up on Ian too quickly, if it was real life)
For Lena I imagine it's easy to keep Robert around. DJ-M the romance will blow up in your face. Club-Rat M, probably fine? Then there's Jeremy, Seymour, Axel, Stan, and I think Louise (or is she only ever your pet?), but I don't think you can heart Holly. But you can slam clam down with slutty-Holly, Ivy, and late game Emma.
Probably much easier just to be an orgasm mercenary, all endorphins, no feelings. Though now I'm trying to remember how a pure Ian/Lena run with no threesomes and playing matchmaker plays out. Alison goes hard slutty I assume. Perry you can push towards Cherry or Emma, and you can soften Wade and Cindy's split. Is this the route where Holly could date Stan? Ew. (this is part of why the Holly Trinity is the best, you can have all the 'twu wuv' and not leave Holly out to be preyed upon by vultures. Robert and Clark?! For a smart girl, she has no taste

[or just desperate for Ian])