I don't mind that so much, I think even 'soulmates' might cheat, lol, adds drama. Or maybe your soulmate is not good for you and you choose not to be with them. My issue is that sims can have multiple soul mates, which kinda defeats the purpose of soul mates (it should be more like fated mates imo), and the fact that you can have a 'soul mate' and when you ask about their relationship or attraction level they're like, yeah, whatever, you're okay (paraphrasing but very underwhelming responses).
I feel like they really dropped the ball w/relationships in general. IDK what I'd do without modders.