Kathy didn't want to leave so why didn't he just stay and move in with her?? doesn't make sense wasn't that the whole point of leaving Shirley??

1 - I don't think he has ever really felt part of the Carter clan and just isn't used to having family around him.

2 - I don't think he is the settling type and this is likely the longest he has stock around somewhere.

3 - He couldn't be bothered facing Shirley Carter (she is too busy fawning over Phil Mitchell anyway.)

4 - Kathy Sullivan likely feels on eggshells around Ian Beale and Ben Mitchell (completely all her own fault.)

5 - The actor was leaving! Haha!

Did thd Actor quit or was he axed?

axed I think