Confused and loosing my self worth!

 Being repulsed by my stbx's every action.  I am playing what I call the "back and forth" game.  It's truly tiring and wripping all the self worth I have out of me.  I am so scared of what my kids future will hold without their two parents being together.  I've longed for a Dad my entire life.  He was killed when I was only a year and a half.  So the fact that I had this dreamy guy or what i THOUGHT was a dream guy back in high school has turned into something that has taken a path all on it's own with BOTH of us at fault.  I sometimes wish I could just blame all the issues on him but being an enabler (me) is just as bad as being the cause.  I am having a moment right now and really need someone to help me through this.  It's obviously holiday season, kids LOVE holiday season as most of us adults should too.  However, all I can now think of is how do I sit him down and tell him I don't want this marriage anymore?  WHat's going to be on the Thanksgiving menu? and then right back to how do I remove myself from this? I don't like having sex anymore, I do it more so once a week if that just to not have yet another negative "thing" in the air.  This morning the reason for my post to you tho is truly mind boggling.  JUST MAYBE it's me but I'd rather get an outside opinion that's worthy of my doubts.  So on the drive to work sbtx and I are going at it because of a simple question.  I may have reacted more than thought through or I may be valid in my reaction and hurt feelings. I asked him "when are you going to get the job application from the hospital that Ms. L was asking you to come get?"  Ms. L is the woman trying to get him a job because she works at the hospital and can get him in as security or housekeeping just to give you background.  His online application for whatever reason didn't get to department it needed to.  He says "I am just going to ask my sister to go get it for me!"  Before you respond his sister has 4 little girls under age 11, her six year old has been back and forth in and out of hospital this month with the flu and touch of pneumonia.  JUDGE THAT YOURSELF! So I then proceed to ask...."why you can't go and get the application yourself?"  He yells..."Because I am tired" In his only defense I will say caring for OUR 18 month old baby girl is a tiring job on top of a new part time (temporary) 3:30pm-9:00pm job he just recently started.  However, we're adults here right?  If someone is saying they're going to refer you to most likely get a FULL TIME PERMANENT job and all you have to do is pick up a job application to get this process expedited wouldn't you YOURSELF go do it and not ask your sister who has ENOUGH on her plate go do it for you?  We have a vehicle she's on public transportation.  He has a wife ME so if he truly were just TIRED what is it that I am here for?  I felt very blind sided and hurt from this.  I basically felt there was no need for me in this particular situation so I parked the car very abrubtly and stormed out of car no hug, no kiss no anything and stormed into the office.  He calls 15 minutes later once he arrives home I guess what he calls "putting me in my place and correcting my anger."  He says I got upset for nothing, he wasn't trying to make me feel jealous but he wasn't ready to hear me say "why can't you do it yourself?"  or "hear me 'trippin' "  I told him "he basically thinks the worst of me, and how can we possibly move forward with a healthy type of marriage and he now not only has to rely on his family members to do things for him but he completely ruled me out as his support system in this?"  Is my rationale incorrect?  Did I just blow off the deep end? I need another opinion because at this point I question EVERY SINGLE thing I say and do around him.  Partly my fault however, what could he have done to not make me feel like a NOBODY without it being a yelling match and a blame it on me fest??  Thanks so much for hearing me!