Sadly, far, FAR too many people fall either totally into the "Just kick 'em to the curb!" camp, or the "Sit idly by, and let him come and go as he pleases, with no boundaries in place" one.
Neither one works -- nor is biblical -- in my opinion.
It's possible stand for your marriage, and for HOLINESS in your marriage, without being a doormat. Having healthy boundaries in place, and conditions by which a wayward spouse is allowed back into your house, your heart and your marriage, is the best way to go.