Why are you asking strangers about this? That's a serious question - people often make the mistake of giving up on friends when they marry and just relying on their partner. Try to make new friendships or rekindle old ones.
All the things you mention are symptoms not causes. Ask yourself WHY do I feel trapped? What could I do to improve the situation? Why don't we communicate? How much of that is down to holding grudges? Try to identify the cause as you see it and then to come up with a solution that is fair to both of you. Then, BEFORE you ask your partner to change, try to change yourself for the good as much as you can. If you are obviously working to hold back that crabbiness, your partner may start to feel better about the relationship and be more inclined to listen when you suggest any changes. You can't force them to change, but if you feel better then that will have an effect on your marriage. You could start with why you feel envious of others. Is it their relationships you envy, or something else such as their financial security? OK, so you're not going to win the lottery overnight, but if you did what would it change that would matter to you most? Without a lottery win, is there any way you could change the things that matter most? For example, if you are worried about debt, you could go and see the Citizen's Advice bureau for help. If it's happy relationships you envy, you could go to Relate (on your own if necessary) to deal with that.
It sounds like your situation is making you stressed and miserable. Get help, get support wherever you can. Go on medication or get counselling if you think it will help. If you can shake the depression off it will give you more energy to start changing your life.
As for shipping out, if violence, drugs or alcohol are involved in your problems (on either side) then seriously consider it. If not, start by doing what you can to help yourself and it will change your relationship ' and your life.