My FH and I have been living together for just under a year (he moved into my house).  My BS7 & BS9 live with me except every other weekend where they have visitation with their BF.  My SD12 & SS10 are here every weekend as per their custody arrangement.  In the beginning things were so bad that he'd bully my kids (he's litterally twice their size), he would destroy stuff in my house, flat out disrespect me, etc.  A few months in after he moved in with me I finally stood my ground and told FH that the choice was his, he either corrected the behavior or whenever his kids were at the