Why in God's world would Heathcliff even for a moment think that HE would end up with Catherine?! After he got her mauled by the dog, locked at The Grange, and turned into a prissy little rich girl? Heck no!
Sad though, their parents died, leaving Hindley to care for the children. But it served Heathcliff right to be turned into slave labor after "Cathy" was gone! He's no blood relation to either she nor Hindley.
But now that they're older, and Cathy is married to Edgar!!!! Heathcliff is all grouchy and decides he's going to come back into her life after being gone for so long, and just ASSUME he'll be welcome in her husbands home, a man who HATES him!
So now Heathcliff takes Edgar's little sister Isabella and runs off to MARRY HER!!!! Well, stupid girl...you'll learn eventually.
And as for Joseph, he's getting on my nerves. Learn English old man!