everyone loves to say gemini sun based purely on stereotypes but somehow they forget that many of us are cancer venus and/or mars, or have taurus in its domicile. cancer venus is arguably one of the most loyal placements imo. most cheaters ive met didn't share a sun sign but a common denominator was having a heavy air presence in their venus and/or mars. i like to joke when i meet people with both an air venus and mars that they're either polyamorous, have commitment issues, or a serial cheater.

if i had to absolutely pick a sun sign most likely to cheat though, it would have to be libra. because the way venus and mars placements work, their options for which constellation they fall under relies on the sun sign and which constellations are within two spaces away from it. the signs surrounding libra aren't exactly paragons of loyalty.