I'm sorry you're going through this difficult situation. I'm sure it must be very hard to deal with, and I'm hoping I can offer some help, but, I need to warn you up front, my words will probably be hard to hear. But I want you to know that they come from a heart of love and NOT of condemnation or anger.
You must understand that you've made some conscious decisions to live your life contrary to the wisdom and direction of God's Word, and that is always going to bring hardship. We live in a world that's full of enough hardship as it is...but when we decide to cast God's Word aside and live our lives by the wisdom of the world, we can always expect additional frustration and heartache.
There are four areas where you have decided to ignore God's Word. I hope you are willing to look at these with me.
1. Marriage - God created marriage as the institution in which a man and woman live together and share their lives. The Bible has a lot to say about marriage, but marriage is defined as two people making a covenant (or binding agreement) to love and commit themselves to one another. (Biblically, such covenants were made in front of witnesses.) Apart from that covenant made before God, you and the man with whom you are living are not considered husband and wife in God's eyes. (See John 4:15-18) The relationship you have with this man cannot exist under God's blessing, because it is unbiblical and wrong.
2. Sexual immorality - Because you are living with a man who is not your husband, your physical relationship with him falls under the category of sexual immorality. Sex is a beautiful and wonderful thing created by God, but it was intended for those who are married. Outside of marriage, the Bible refers to a sexual union as fornication or adultery depending on the circumstances. You need to read 1 Corinthians 6:9.
3. Unequally yoked - You said in your note that the man with whom you are living "believes in God." Did you know that Satan also believes in God?--but it doesn't do him any good. (See James 2:19) There are many people who claim to believe in God, but that doesn't mean they are Christians. A Christian is someone who is trusting Christ for forgiveness based on His death on the cross, and who has dedicated their whole life to following and serving Him. Does that describe the man in your home? Is he passionate about loving God and living according to the guidelines of God's Word? Is he a man of prayer, devoted to knowing and obeying God's Word? If not, then as a believer, you and he are unequally yoked. (Read 2 Corinthians 6: 14) This is something forbidden in God's Word.
4. Forsaking fellowship - Lastly, the Bible explicitly tells us not to neglect regular church attendance. (See Hebrews 10:25) As Christians we all need a place where we can be fed the Word of God and encouraged each day to walk in wisdom and obedience. Those who stay away from church are being disobedient to this directive.
Even after all this, I want you to know that God loves you and wants you back. He is waiting to forgive you and restore your life to you. But that act of returning to God could very well be the hardest thing you will ever do. Because it will mean denying yourself the one thing you want most...the man with whom you are in love.
But Jesus asked this very important question: What good will it be for a man if he gains the whole world, yet forfeits his soul? Matthew 16:26 (NIV) In other words, what good is it if you get everything you ever wanted, and you end up losing your soul in the end?
Let me outline the steps I believe you should take to resolve this issue and return to God:
1. Confession - The Bible says that if we confess our sins, God will be faithful to forgive us and cleanse us from everything we've done. (1 John 1:9) Pray and tell God you're sorry for taking your life into your own hands and living it contrary to His Word. Ask Him to cleanse you and wash you from your sin and He will do it. That's why Jesus died on the cross -- to pay the penalty of our sins. He will forgive you and you can have a clean slate and a clear conscience.
2. Leave behind the old life - This is the really tough part, but God will give you the courage and strength to carry it out. You need to separate yourself from this man immediately and get yourself and your daughter to a place of safety and sanity. Don't wait and don't waver.
3. Get connected - Find a good Bible-teaching church and get yourself connected. (If you need help finding one, I would be more than happy to assist you.) I would recommend that you call the church and tell them you are separating yourself from an unbiblical relationship and need prayer and support in your efforts. Tell them you want to leave your life of sin behind and walk with God and that you need all the help they can give.
4. Fill up on God - You need to start reading God's Word every day with your daughter and praying together with her. You do NOT want her to make these same mistakes, and it's not too late to make changes for both of you. If you don't have a Bible I will make sure you get one. Please let me know.
Remember, God loves you! Return to Him with all your heart and He will direct your steps. Proverbs 3: 5-6 says:
Trust in the LORD with all your heart; do not depend on your own understanding.
Seek his will in all you do, and he will show you which path to take. (NLT)
I will be praying for you to make the right decisions and to walk in obedience to God. He will help you as you trust in Him.