A lot of false assumptions are often made when people are talking about BDSM. Let's start with a little glossary to be sure we're all on the same page.
Never believe: "I love you, it will never happen again." It will happen again. The tears don't matter, the bruises don't matter, the broken bones and ER visits and warnings from friends and relatives don't matter. Those scars that we bury deep inside us, the mental and emotional scars that we try to pretend don't exist -- they don't matter. It will happen, again and again and again, unless someone puts a stop to it.