Need Etiquette help... parents of bride and groom boutenierres...

So I know that parents of the bride and groom get boutineirres typically.  (Or at least I think, maybe I have that wrong too.) What is the protocol if his family has his mom and her new husband (who was never his step dad because he was already living far away when they married) and his dad and his long term girlfriend (again, they got together after FI moved away from home).  I don't want to disrespect these people but they are technically not "parents"... Any help would be greatly appreciated... Do I even have this tradition correct?

my mom is currently married to a guy she met long after i was out of college and living on my own.  I am NOT ordering a bout for him.  (not to mention that he's kind of a jerk to me, but that's a story for another day!)  He is not involved in the ceremony in any way, except basically as my mom's date. 

So I guess, if those folks are involved in your ceremony, or in any way financing the day, you might want to just get one for them, it doesn't have to be the same one as everybody else's...maybe just a bit of stephanotis.....Just my opinion. :)