how far are the wives outside the city? that’s an important factor here to determine their relevance in this specific fight.
Also, the OP does not state that Regulus protects his wives, at least not in the thread description itself, if that was just mentioned somewhere in the pages of discussion, then the OP should actually add that detail to the main post because it changes how the match is perceived (i'm talking to the OP if he is reading this), however, even if Regulus did try to protect them, how would that logically lead Tatsumaki to the conclusion that his invincibility is tied to them?
There could be many reasons he might try to keep them safe, and none of them would immediately suggest they are the source of his power, they could be important to him emotionally or personally, meaning he just doesn’t want them harmed, they could be a part of a ritual or serve some strategic purpose beyond combat, they could simply be non combatants that he doesn’t want caught in the crossfire, which is common in many fights.
If Tatsumaki waz sensing something abnormal about them, like spatial distortions similar to Regulus, then I could understand the argument that she might suspect something, but she wouldn’t sense anything unusual about them at all, they are just normal people, so the idea that she would immediately link his invincibility to them just because he cares about their safety is a huge leap in logic. They die in the mass destruction and the heart goes to the other wives (if they are in Range...hence why im asking how far they are)
Tatsumaki dodging Homeless Emperor’s danmaku isn’t the same as dodging Regulus’s attacks (This is the only danmaku didging feat i know from her via google, so if there are more im unaware of, please show me.) She wasn’t actually dodging anyway, she was just flying way faster than the projectiles could reach her. The difference here is that Regulus’s attacks are 843 times faster than her in every speed stat, and they come in the form of things like raindrops or sand grains, making them nearly impossible to see or avoid.
Even if she can sense spatial distortions to track them, extrasensory perception doesn’t boost speed, and she’s still too slow to react. Every single grain dura negs, so the moment she underestimates him, which she tends to do i'm assuming (I remember her saying something along the lines of "why would i run away against someone weaker than me" against saitama), likely due to the fact her movement speed is just so much faster than his reaction speed, so she'd be Blitzing the hell out of him and come to the conclusion he's slow asf and not skilled at all, but invincibe), she'll probably be in the air ranting and all regulus needs is one attack or danmaku and she’s getting erased before she even realizes what happened.