Thank you for your letter, and I hope many who are reading this will stop and pray for you and for others who have a family member in prison. You bear a heavy burden, and the Bible tells us to "Carry each other's burdens, and in this way you will fulfill the law of Christ" (Galatians 6:2).
May you find your strength in Christ during this difficult time. God knows your situation, and He knows your heartache and loneliness. He knows also the struggles you face the financial burdens, the problems raising your children, your fears about the future, and so forth. You need His wisdom and strength during this time and He is willing to grant it, because He loves you. If you have never asked Christ into your life, do so today.
Then don't be ashamed to ask for practical help from others when you need it. Your church is a good place to start; it may have groups of volunteers who would be delighted to fix things around your house or help in some other way. In addition, reach out to others who face similar challenges single mothers, for example, or wives whose husbands are away in the military.
In addition, do all you can to encourage your husband and assure him of your love. Most of all, urge him to put his life in Christ's hands. You can't change the past, but with Christ's help there is hope for the future.