I'm a wimp

I'm just a wimp...and why is this text so large..LOL!  Why can't I just tell him to f-off or be as mean as a pitbull or anything.  I've done that before, what makes this any different.  Maybe it's the fact (the only fact) I have children with him and have to TRY to be as amicable as possible for their well being.  I guess I have no backbone, like I used to in the past or has he broken me so bad that I've just given up on everything.  I don't know.  I always always said I would never take any crap or this crap and here I am taking it...wondering.  Now I'm headed to see my parents with the kids for the weekend giving him free reign of the house.  Will he have the nerve to bring her here like has happened before?  Do I care that they will meet?  Yes and no...do I expect it...yes...do I care, a little of both....just in the fact it still hurts but also there is NOTHING I can do to stop it.  Oh well.  This weekend will probably NOT be a good one, as I DO NOT get along with my mom and she has already started about having kids in her house for the bday party, since it's going to rain.  I think I'm turning into her and I hate that...absolutely hate that....she is a bitch and I hate to call my mom that but that is EXACTLY what she is...never a nice word or ever a nice tone to her voice or anything.  I do blame her in a sense for the way I am...a wimp because I 've always tried to please her by getting good grades, good in sports, being a good person, and I never ever got anything from her but grief and being yelled at.  I was never good enough...maybe that is a deep seeded things now...I'm not a good enough wife, mother, person etc.  that he had to go somewhere else.  I think I look for reassurance but I know I will never get it from him or her...that is a hard pill to swallow.  It's nice to be recognized once in a while.