OK so Chris and Jane aren't even divorced since he's calling her his wife? Just separated and still living together? I suppose it would be too long winded to say "I need to clean up the house before my ex wife who I've separated from because I'm gay but we still live together, and my overgrown adult toddler who bashes me on a regular basis for not mollycoddling her are coming up from Brighton."
I think that Gabby hates her dad because he still has some of Jane's attention. She's so adamant to make it seem like Chris is this awful person that Jane needs to be protected from, and yes, he is pigheaded and all of the things we've said before, but he speaks about Jane with much more respect than Gabby ever has, and still lets Gabby stay in their house when she visits.
TDLR; Chris and Gabby are the same person, both who want Jane's attention 100% of the time.