My take is that there is a unrealized subversion in this relationship based on the line

"Remember Perin @ 15, the Academy firebrand?"

The concept is that After Order 66, Perrin and his "regimental mates" were 100% about to stage a countercoup on Palpatine within hours/days of him declaring the Galactic Empire.

And Mon begs and pleads for him not to do it. He can't hold onto power, within 18 months he'll slip up and we can get him through the courts, the surviving Jedi will regroup and kill him in a decapitation strike on the Empire etc.

Perrin, you don't need to risk your life, you barely survived the war, so many died in your regiment/army etc. etc.

And Perrin, the firebrand, says no. I kill him tomorrow, or I die trying. That's what is right. If people will not defend democracy with their lives, then they don't deserve it.

And Mon drops the bomb.

I'm pregnant.

Do you want her to grow up without a father, I need you. She needs you.

And he relents. He trusts in Mons political acumen. Mon is good at this political stuff, if she says he's gone in 2 years, she's probably right.

Cue 15 years later and that's how I see you get to Perrins specific on screen personality accounting for all on screen characterization.