First post so hoping for some constructive feedback and i am sorry if it is long but its a really stressful time for me.  My SO and I are both divorced and have been together for 3 years now.  He has one Bio and I have 3 from previous marriage, all under 11.  He used to get his step-kids, however they no longer come.  We got engaged and his mom knew it was coming and all she talked about that entire night was his ex wife (they were married 1 1/2 years). First, we are not blending.  His son (8) is his only child so he babies him to no end and lets him get away with just about everything, very little discipline.  My kids on the other hand cannot seem to do anything right.  He only gets his son every other week so I understand some slack, but he comes back from BM and has no manners, urinates all over his room, does not listen to anything I say and says very mean things to my boys (7 & 8).  I have my children full time less some weekends they go to their dads.  My kids are far from perfect but DF constantly yells at them and even ignores them when his son is home.  He will take his child to the beach or fishing etc, but only invites my oldest boy fishing when his son isn't home.  DF mom has been around my kids for 3+ years and still doesn't included them in anything or consider them family.  My DD has asked to spend the night and its "not tonight" or some other excuse, but if her bio grandson asks its "of course".  He has toys etc at her house and my kids have nothing to play with, she doesn't interact with them, and still insists in front of my kids she only has 6 grandkids and is taking them to the amusements park / beach (4 bio grandkids and my DF ex-step children)  I have addressed my concerns with DF and his mom and it gets spun around that i am making something out of nothing.  My kids notice and it is unfair, including at birthdays when they don't get a phone call or anything but she shows up with cake and presents for DFS.  My children unfortunately do not have a lot of family here so really all they have is me.  My DD (going through the teen phase) makes mistakes and DF doesn't let her live it down and constantly calls her a liar, a thief and is also telling everyone so and so did this and she did that.  Every time we go to his mothers he has to bring up something she did wrong, and I've had enough.  We used to be a family of 6 and it feels more like a family of 2 and family of 4 living under the same roof.  I am seriously ready to throw in the towel and move along.  I work from home 45+ hours a week and he works second shift so I have my children during the day and on his weeks i have to pick up his son, care for him all week, and drop him back with his mom the following.  The deal was he'd help with the kids during the day since he switch shifts, but if his son is home he gets up around 8 and is gone the rest of the day until he has to work and when his son isn't here he sleeps till he has to leave.  I feel very used and frustrated.  I have asked over and over to go to counseling for blended families etc and he refuses.  Things were great in the begriming, but it seems the longer it goes on the worse it gets.  Currently due to me bringing up the issues with his moms unequal treatment towards my children he hasn't spoken or even shared a bed in days.  Anyone else have these issues? Is there any hope? What else can i possibly do? My children are tired of his attitude change when his son is home and have been telling me they are starting not to like him at all.  They love that he is working nights now so that when i get off work and we have dinner it isn't stressful anymore.

And before anyone asks, aside from the household expenses which are 50/50, i pay for all my children stuff, sports and my own vehicle, etc. including his sons clothing.