I think Dianne is probably quite hard work in a relationship - she seems very insecure and erratic and she's ruining their house with her projects. We've also seen her display controlling food behaviours around him which must be really difficult.I don't think they have split- but I wouldn't be surprised if they've purposefully taken time apart to assess what they want going forward. They both, especially Joe, seem to have lost their spark. I've been watching Joe in Zoes vlogmas and he truly seems to be a shell of his former self. I don't know if it's trouble with Dianne or something else, but he doesn't really seem okay.
They both look terrible after long periods of time together so while they might love each other, I'm not sure it's a healthy relationship and there are things they will hopefully acknowledge and address.