Well, what exactly makes you think that your step-father’s maladaptive sexual behaviors/ desires for children ( and you, who he’s had an inappropriate fixation on from the time you were a young child and adolescent), just… vanished? Those types of sexual behavior problems are incredibly challenging to manage (even with extensive specialized treatment/ intervention) let alone treat, especially at the age of someone who is clearly a grown adult male who stopped sexually, physically, emotionally, etc. developing several years ago. He is decades past a childhood development stage that would even indicate that those types of problematic sexual behaviors could be viewed as possibly less serious/more treatable and preventive in adulthood if they are promptly taken care of and helped, because even in childhood those sexual behaviors are a problem.

That being said, if he hasn’t gotten long-term extensive, thorough and specialized treatment, there’s an incredibly high probability that he still has these thoughts and even urges. Even with that kind of help the chances are small at his age ( old enough and mature enough to get married and raise a third grader, and then have “grandchildren”). I am also guessing he has never gotten this kind of help for such a complex, deeply ingrained, PATTERN of sexual behavior problems, anyway. Now we are talking about a large chance that your children will likely be exposed to this one way or another, if you continue to have this man in their lives. Children do not have to be physically touched to get traumatized and/or at the very least, cause significant damage during developmental stages that are so incredibly complex and crucial to their overall emotional and personality development.

A person as your step dad with that kind of engrained pattern of behavior, has a high chance of increased impulsivity. Impulsivity enhances the odds of disregarding various types of boundaries.

That being said, what makes you think this man all of a sudden developed a respect for one’s personal boundaries? Especially after going decades without having even the slightest regard of other’s boundaries and safety?

Your mother- also spent DECADES watching her husband act predatory, on multiple occasions, toward her own child, and chose to ignore these deeply disturbing and harmful sexual behaviors toward HER CHILD, which ultimately led to her repeatedly disrespecting and/or completely disregarding her own child’s boundaries (and overall basic human rights). Has she done anything at all to address this long pattern of damaging behavior? She’s still with your step father after watching him behave like this over and over again, so that’s… telling. Has she ever even acknowledged these traumatic experiences that you had with him? Did she own up and apologize for her negligence as a mother? Did she do anything at all to address these serious issues of hers? Again, she’s still married to this guy and even fighting with you and knowingly putting her relationships with her own daughter and grandchildren in jeopardy , for the man who “overstepped”.

You should maybe ask yourself why you feel the need to keep two people in your life that put you in danger over and over again? Who clearly never respected you (body, mind, etc.) Two people who willingly put YOU ( your entire childhood/ adolescence) in actual physical danger and at severe mental and/or developmental risk? Your mother still seems to have a huge lack of respect toward you and even your own children, for even fighting with you in the first place over a child PREDATOR. The fact that your own mother doesn’t care that a predator is around not only her child (you), but your children, should seriously make you question her motives and overall character as a human being. You should also seriously explore why you are willing to have your own child around a predator, for your mother. Let alone a mother who never respected or protected you. Why is your mother more important than your children’s mental/physical health, development, and safety??? It is impossible to create boundaries with grown adults who don’t CARE ABOUT BOUNDARIES. Clearly.