RSBM
I think this is key.
IMO At first, PF enjoyed the kudos of having an attractive girlfriend who was in another league, professionally, to most of his crowd.
As the relationship lost its newness (relationships inevitably do), and domestic
obligations became the norm, he started being mean.
He may have found it particularly satisfying to make a pregnant woman/new mother cry.
Maybe one of his nasty refrains was to tell her she was hanging on him like a leech.
She bought the townhouse, possibly hoping that asserting her independence would help put the relationship on an even footing.
This probably made him feel exposed and inadequate. His behaviour became nastier.
It would not be surprising if she felt low or if she took anti-depressants.
She may have sometimes wanted to get away. (Her mother, when asked if Kelsey had ever gone missing before, pointedly said she always knew where Kelsey was).
If they were on-again/off-again, she may have started accepting more invitations to socialise with colleagues.
She probably couldn’t deal with his moods and aggression any longer. Perhaps she, reluctantly, started to talk about ending their relationship (possibly hoping it wouldn’t come to that), and how they would manage custody.
It suited him fine to keep her dangling, but once she started to call some of the shots he became angry and resentful.
For PF, the thought of Kelsey telling people she dumped him (and maybe getting herself a better boyfriend) was nearly the last straw.
The thought of her taking the baby away filled him with the ultimate rage.
I speculate.
Wonder how they're doing these days?
