Kates not dumb. she has sense enough to know what is trustworthy.
Taking a balanced point of view, Jonny has shown actions that could be jealousy. but they have a good rapport between each other, and each knows the others limits. they have developed trust, probably as best as any other 2, i think. they also know best themselves what they mean to each other. Altho Jonnys jealousy might not be sexual jealousy, it isnt intrusive or constant. there could be a"when harry met sally" thing, but he is not a lech.
Some posters(not of this thread) here are a lot freer with their name-calling, put-downs, and sometimes malicious slander, than others. downright ugly. about as much entertainment value as the ugly bitching in the house. cant stand this trend. the housemates seem to come across better sometimes. Thats saying something.