I hate being treated like a kid. How do I get out?

I'm 30 years old. I have been married for 12 years and have a 4 year old daughter. I've been telling my husband for a couple of years that I want a divorce, but he will not agree to one. My dad is a local holiness pastor and of course, does not believe in divorce. We really have a good set up here. My dad has bought us a house and given it to us, so I kind of feel obligated to him. I have recently met up with an old friend and starting seeing him. I know this is wrong, but I also know that I don't love my husband. Everytime I mention divorce, he runs to my dad and tells him like we're little kids. Yesterday, my dad told me that I didn't need to leave my house. Why am I treated like a child and a prisoner in my own home? I just don't know what to do.