My step son is very controling when around all other children, including my son. My other half doesnt see it. Pls HELP*

My problem is my step sons behaviour.  I dont know how to handle it or address my boyfriend on it.  I have two children ages 13(girl) and 10(boy). My stepson is 7 (boy).  Our sons get along great....as well....   We just bought a 4 bed home..which helped with the stress regarding where my stepson slept..but there was and still is other issues with him..... My bf loves to pamper his son when he has him (of course) as he only gets him everyother weekend..and one day a week.  The thing is he blows up alot not only to my son..but anyother boy that he plays with......family member or not.  an example is - two boys playing xbox..but he yells and snapps at the other boy for grabbin his guns etc... it is not as basic as i state it...it is ALL the TIME...controlling the other child all the time...and when my bf  takes care of it....it is always the same...share and everyone b fair or else its gone etc.....the problem for me..is that it is the stepson ALWAYS bullin the other kids..and yelling..and even makin up lies to get what he wants out of it from either them or his dad....PLS help.. how do i address the issue without making a huge deal.  I adore his son..but anybody else around and he acts out......thanks

[specialmom]

It's always trickier with step children.  You never know exactly where the boundary is. What about talking to his dad at a time when the boy isn't visiting and it is just the two of you talking family business?  Ask him what he thinks of his son's behavior and if he and you could help him handle his frustration with other kids better.  That way, he won't get defensive and it isn't in the  heat of the moment and it doesn't sound like you are just bashing his kid but trying to help him.  Then come up with a plan for dad to work on it with him to help him handle his emotions in a better way.  See what ideas his dad has and go from there.  You two have to work as a team for the kids.  good luck