@dr_mon3y I can understand it somewhat.
The last thing his love told him was to protect Aries. As a father any man should go above when it comes to protecting their children. He's the new ruler of a country so protecting a prince should be high priority. But she also wasn't the empress, some other lady was, if anything that's what's weird to me.
If he was stepping up to take charge of a nation you'd think he could just replace whomever was there in the first place. Maybe a ruling caste or whatever made that current empress a condition for his taking charge for keeping the bloodline pure or whatever BS that usually entails. So his actual wife becomes a mistress and the empress becomes the "wife" in order to produce an heir.
The fact that he couldn't protect his real wife from assassin's would've been a wake up call that he couldn't protect his son either. Especially with his injury and if my earlier guess is correct, then the castle staff probably aren't fully loyal to him either.
So the option to hand him over to his trusted companions makes sense to me.
Sorry for rambling. I love theorizing, watch everything get explained in the next few chapters.

@Harlock lol naw, I think we've established that they're here for his protection. Serena clearly hasn't given up on Hiro and they all know it.

@Harlock considering the fact that he prefers hunting groups of space pirates as a "safe" activity. I think he doesn't really want to get too involved in it.
If he came out with the data he's aware of it feels highly likely that he'd be placed at the forefront of a new branch and that's gonna increase the risk he takes. While he himself probably wouldn't mind I doubt he'd want to put the girls through that.

@BADflatASS the harem trope is tricky. So many series like to try it but I feel most of them just don't pull it off effectively.

@S_Logic making Angel be the harem hero instead of herself actually doesn't sound that far off. He's clearly powerful, she seems not to mind sharing him if someone cares for him the same as she does. Looks like that's where we're going.