NRaas SP will change relationships, but only "offscreen," so to speak. Sims will get engaged or married, or break up, without performing the interactions themselves. And of course SP isn't going to change a relationship in your current household while you're playing it; that's your job. If you want your active sim's new guy to propose without your directing him to do so, you'll need a different mod from another source, although I don't remember which one. But I've seen it mentioned here before, so someone else will definitely know.