What to do?

I've been married to my husband for 3 years  and of course I love him, but our entire marriage has been rocky. There's days I love it, but days I'd rather give up. He's never beat me, but he's slapped me on the leg or arm and it's like he's my parent and that's me being disciplined. There's times he's grabbed me, too. He also recently cheated. I feel trapped. Everyone says to leave, but no one knows how hard leaving is. How could I afford to move out or take over house payments or pay all the bills? We struggle now and both have full time jobs. Any advice?