Firstly there is no right answer. However from the inside of a difficult situation it may be hard to see any other views and, given this, I will impart my opinion for whatever use that may be.
TLDR: Your life has potential to do good whilst you're alive and none whilst you aren't. The latter will happen eventually so don't rush it, all you can do is what good you can with what time you do have.
I've cut what you said down to what I consider the key points:
married ... loves me a lot. I have very loving parents and siblings (but live in a foreign country).
Big point here, if your family and wife love you a lot is there not more pain caused by your loss? You might not place a huge value on your life just from your own point of view but it would seem they do. Do they not lose out on that happiness?
jobless ...physically unfit ...I consider myself a lame horse.
Perhaps part of what you consider worth is due to your job but if your wife were in the same position would you think everyone better off without her? It is a question of perspective and your view of yourself seems skewed. The phrasing of the bolded part of the quote shows your opinion of yourself to be biased towards low - possibly you are depressed. Therefore I think we can safely assume that any indication we get of value of your life which comes from you cannot be used to infer some objective overall utilitarian 'good'.
My in-laws who are relatives from my father's side hate me and want me to divorce my wife. I am living with in-laws since the day I arrived in America (October 2009).
I'm sure this isn't helping your opinion of yourself, being surrounded by these negative opinions. Whether they do hate you, of course, is something we cannot prove given we have it only on your testament.
Seeing the suffering of my family ... I came to the conclusion that it is better to sacrifice one to save many from suffering.
should I end myself and save others or just wait and watch them suffer just because I choose to live.
Now we come to the important bit. You are assuming there are only two options but the situation you describe isn't some narrow viewed trolley problem. You have the power to change many variables.
It is difficult to fully deduce but it seems to me that neither carrying on as you are nor dying are good solutions.
Carrying on as you are seems to be causing some conflict at least between you and your wife's family. You don't seem to be happy with your position....however death is easy for you and terrible for your loved ones.
But there are many other options of what you can do with your life, whatever your ability. There are many ways to improve yourself, to contribute and solve the conflict between you and your wife's family. This, I believe, leads to the greatest good for the majority. There is never sufficient evidence to suggest suicide is the best solution from a utilitarian point of view in modern society. Whilst alive you have potential to do good, if dead you have no potential for good. You just have to choose to use that potential to do good whilst you are alive.
P.S. I am not a good man, in my life I have done almost none of the good deeds
So? Now you can start. The future is where the potential lies, not the past.
(The bold or italic text indicates where I thought you you were using emotive language that indicates a bias of your testament to the situation. Try thinking of it as if your wife was in the same situation as you, what would you want to happen?)