RSABBMBMFF:
I do think that the fact KB bought her own place without PF's involvement/investment is a strong indicator that the relationship had at least cooled to some extent. Certainly, there's nothing that supports the idea that marriage between the two was imminent. IMO, it's a mighty long engagement for a couple that already shared a child and where one of them at least had the resources to support a family home.
I haven't read anywhere that they had set a wedding date.
I haven't read anywhere that she had an engagement ring.
Their "engagement" seems a little nebulous.
I have wondered about PF's intentions r/t living on the ranchette.
Curious to know whether or not PF lived somewhere else at any point in his life, i.e., if he ever moved away initially after finishing school and then came back to the ranchette later on to (ostensibly) help mother.
If he's never moved away from mother and the umbilical chord has remained firmly intact, then I do think he may have planned to stay there forever. He may have a rigid personality type that just can't deal with changes or disruptions to his routines. Then again, he "moved KB out there" and had a baby with her, which posed definite changes in his routine. Hard to say. It's just flat weird. Coloring within the lines of TOS, with that, I'll put my crayons down.
All of the above: JMO.