I don't understand why ur inlaws n hubby want u to go there? Why do the inlaws expect u to go n stay there without ur hubby? I have never in 8 years of marriage been to pakistan on my own. Hubby goes every year, n I go every 2-3 years. It's his family. N we couldn't all afford to go every year. Anyway, I always get sick when I go so I have an excuse, but still it isn't expected.
U need to stand up for yourself. Tell him to be logical.
Like others, find a job...be independent...more importantly, try to stand-up for yourself, if you don't then none can help you -- I am talking about this from personal experience.
I would be allowed to go home only twice in a month - parents live 5~6kms away from home. Then I fought and argued with my husband who was Alhamdulillaha supportive in my argument points and now he makes sure I visit home every sat/sun for atleast 30 mins if not more..:D
Be firm in your decision not to go.
You are a grown adult and I'm guessing a UK national? So he cannot by law force you.
Just keep yourself busy in your life. Forget about everything else for the moment and don't take any notice when him or your in laws keep bringing up the topic. You are giving them the power to control and run your life when you don't have to. Stick up for yourself and your rights.