If you have an unhappy marriage, you only have two choices. Make sure the changes you desire are made or leave the marriage. How do you decide which route to take? Do what you need to do, as no one deserves to be unhappy in a relationship.
If there are children in the marriage, do what you can to make life less stressful for them. This does not mean you have to stay in the marriage for those children. Children will know if something is amiss, no matter how much parents try to hide it. Children deserve the best parents possible. If those parents cannot get along that is no place for them. Only you the parent knows when its time to give up, no one can tell you. Follow your brain in this case, rather than following your heart. Sometimes in these situations, the heart can lead us astray.
Open honest communication is always the best policy in any type of a relationship especially in a marriage. If you feel that you cannot say what you wish to say without the fear of upsetting a spouse that is a big problem. How can you even think to solve the problems that make you unhappy if you are not free to say what you think?
Learn to trust the other person, if you feel they are lying to you let it go unless you have the proof. Without the proof, you have no supporting arguments and perhaps you are wrong. Perhaps its your over active imagination, and there is no sense in throwing away a salvageable marriage unless there is proof.
If money is the issue, go get a job if there is not enough for the families needs. If you are unable to get a job outside the home, find work you can do at home. Freelance writing is always an option if can write 400 words or so on any topic. Babysitting, sitting with an elderly person or doing errands for someone who cannot get out on their own are always options.
Money is a big problem for couples, and is about the number one cause for divorces because either one person is spending a lot or the one working cannot support the family by themselves. If this is, what is making you unhappy this is easier to fix than a cheating spouse is.