I need legal advice...I have two children with the same man:not married, have lived together off and on BUT...

I have copies leases w/ our names, i have a noted calendar w/ all arguements confrentations & promises made & broken I've carried our kids on my health ins. until this year, I do all, incl. being a daddy. I have put up w/(don't ask why)many other women & have pics, notes, & old hotel rcpts pertaining to him& these women, i have been told yr after yr that things will change & we would marry(i've NEVER pushed or nagged that topic)was told that all is wrong because of me"2 manly 2 fat 2 shitty 2 ugly," im ugly when he talks to me crazy,this has been ongoing for @ least 8 yrs(been 2gether 18 our kids are 5 & 1), we have no house(live in 1bd apt)he does stay over at times, he lives w/ his dad, we split bills 50/50, he has a navigator, a truck he's fixing, a bbq truck & had a vette, he has a reg day job & works as a bouncer/personal security @ clubs, cash under the table. i'm at my breaking point, i want to cut ties & file childsupport & want the max or more. we live in TX. how do I start?