oh dear.
first of all, try to be patient. a lot of people are in your same situation, and a lot of people have in laws who feel the exact same way that you do.
next, revisit the issue with your husband, at a time where you are both able to concentrate on the discussion. a good time ive found to talk to my husband is when we are driving. get someone to watch your children so you and your husband can be alone to talk. remind him of your conversation from before you quit working, and ask him to update you on his feelings about this here and now. do it softly. ask him if he feels the same way, and if not, why he doesnt feel the same way, then try to come up with a solution.
the next thing you want to do is to tell him plain and simply that you need him to support you if this is the way you both want to continue. i beg of you not to separate from your husband so quickly.
my feeling is that hes not changed his mind, but he feels pressured by his family to feel the same way they do. i fear that separating from him might make him feel as if you simply dont love and respect HIM as a person. that this issue that is rooted in someone outside your marriage is something that splits the two of you. NO outside issue should EVER come between you.
i understand that things may seem intolerable now, but when the two of you can talk and come to a solution things should settle down. men tend to be the ones who feel the responsibility for their families, perhaps hes feeling a bit more pressured since the financial situation in your marriage is different than it was before. maybe he just feels pressured! :D
one resource i feel you NEED to use is the things that mark gungor has. he is FANTASTIC and one of the programs that he has is "laugh your way to a better marriage" and it is SO funny, and SO RIGHT ON. he has a way of putting things that makes you go AH HA! you know? he explains the differences between the ways men and women think, and how the operate, etc.... it will totally change your ideas about men and women, and can make you and your husband closer, especially if he watches it with you. if you guys like comedies, or comedians in general, (i mean who doesnt like to laugh) this guy will be awesome, and your marriage will strengthen.
one thing that you want to avoid is pointing any fingers at his family. i agree that they are being HORRIBLE to you, but what you need to remember - what is important in your marriage is less what other people are doing to you and more what YOU need and what YOU feel. men cant read our minds, he might not understand how you feel. use "I" statements, not "you" or "them" statements.
i hope this helps somewhat. the good thing about marriage is that it is a partnership, and it is meant to be forever. marriage is HARD!! the Bible itself says "it is good for a man not to marry..." and later continues "because he who marries will have trouble in this life"!! God Himself tells us right there that marriage is hard! :D we cant expect things to be perfect. but just because things are hard, frustrating, 'unbearable', doesnt mean your marriage is over. it means you have an incredible opportunity to strengthen your marriage! :D
its quite possible your husband is depressed too. so just try to be sensitive.
one thing that mark gungor talks about in his video (its around 50$ but its around 6 hrs long...) is that men feel close to their wives through sex, and women feel close to their husbands through the loving things they do. in order to get sex, men have to give their wives the loving things, and in order to get the loving things, wives have to give their husbands sex :P it sounds silly, but its true. even, at this point, if you simply dont want to, dont feel like it, do it anyway. its amazing the wounds that can be healed by paying attention to our spouse's deep needs in a marriage.
its helped even through the little things in my marriage, and the big thigns too. if i just give in, and make love with my husband, he is nicer, sweeter, kinder, more romantic, and loving to me. when i dont, hes hurt, rejected, angry, distant, etc. so, ive learned quick that if i want my husband to do the things for me that i want, i have to give him the things that he wants. he has also learned too that if he wants me to make love with him, he has to be nice to me. ive told him the one thing that gets me every time is if he kisses me on the back of my neck when im making supper, or washing dishes or something. gets me every time!!! if you have some trigger that makes you get the shivers, tell your husband what it is!! let him use it!! :D
anyway, i hope you check mark gungor out. changed our lives, and i hope he can change yours too. dont give up on your husband. trust me, with 4 kids in the picture, its much easier to work your hearts out to make it work than to just give up. no other man on earth is going to be any better, so dont think that the grass is greener. its still grass! :D :D
good luck. have patience. talk it through. tell your husband what you need, and figure out what his needs or worries are. :D dont let the world tear you apart! your inlaws problem with your job is THEIR problem, not yours. its THEIR feelings not yours. dont be responsible for their feelings. maybe they are simply jealous that they didnt do things that way. who knows. it doesnt matter. what matters is YOUR family, in YOUR home, doing what is best for your family. :D you GO MOM!