Maybe she thought things with Slenderman Geoffrey would improve in a new house- I've seen friends do this before, blaming living situations/not living together on a relationship feeling off. Unfortunately though, most of the time moving house doesn't fix anything. Same as having a baby to fix a relationship.
I get really really weird vibes from Geoffrey the doorstep lurker, so many things he's done have raised red flags, and that's only the stuff we have seen. I dread to think what he's like. Kathleen is clearly bored in her life but she now seems miserable, drained and has lost the spark which made people follow her in the first place, and I can't help but wonder if G has caused it. Perhaps she thought a big house would make it less claustrophobic but it hasn't changed anything. (Too speculative I know. But I just can't imagine living with someone like him, he gives me the creeps)