Counseling with a professoinal counselor.
Talking to the pastor of your church, or the marriage/relationship pastor if you have one.
Getting connected with a marriage-mentoring couple from your church - some older couple who has worked through difficulties and stayed married and are willing to help you.
You don't say a lot in your post - but it seems like you are trying to change yourself to fit what your husband wants. You don't say so explicitly, but I get the sense that your husband isn't exactly committed to being a selfless, Loving, sacrificial partner. My guess is that he tends to be negative and complains a lot and usually blames YOU for circumstances and his unhappiness.
If that is the case, then I assert that you will NEVER be good enough for him because what he wants you to be will always be changing. You will always be a step or a half-step behind.
That is because the real cause of his misery is not you or your marriage. YOU don't 'make' your husband miserable - he does.
First thing I'd do is get yourself right with God and live the life of a Loving, selfless, gracious wife. Note, that doesn't mean changing yourself to fit what your *husband* wants - it means becoming the woman and wife that GOD wants you to be and Jesus teaches you to be.
At the same time, you could try to get your husband to go to counseling either with you or, at least, by himself.
You have to stop wondering whether he wants to stay married, and ask him outright. And if he does, then ask him if he will work with you to better your marriage. And if he will, then see the suggestions above - counseling, mentors, etc.
If he says he doesn't want to stay married, all you can do is to live the life of a Follower of Christ and be the Loving, selfless, gracious woman and wife you are called to be.
Love God; Love people.
Seek first to understand before you seek to be understood.
Step 1: Toast the Poptart.
