injustice

im doing my kids, my stepkids, my husband and myself injustice in staying in this marriage.
i should not have married in haste and give in to his pressure of marrying too quickly when i havent even met his kids.
and not knowing exactly what i am getting myself into.i didnt even know if i want to be a stepmom.. the thought didnt enter my head until i finally met his exwife and kids.. but twas too late.. were married and i was pregnant.. the reality that his exwife will always be in our life and i am but a second wife hit me hard as its like im sharing this marriage..i cant and wont have my own little family of my own.. not exactly what i want. call it selfish..who wants to be a second wife?and wont you rather be a mom than a stepmom?
so it was too late when i realized i didnt want to be in a stepfamily..
and husband's controlling,manipulative and arrogant attitude doesnt help.the many bad blood between us, the condescending joke and name calling, the  manipulation and patronizing... his favorite daughter.. aka.. possessive jealous mini wife, and the bitchy adopted daughter arent much of a help either.
i know we need to sepa
rate..were both miserable. were totally incompatible. hes agnostic, im traditional catholic, he has vices, i dont, hes values and beliefs are different than mine and i came from conservative traditional family, he grew up from broken home with string of stepdad and stepmoms.  his other kids have different moms except our kids who are full siblings. and he doesnt get aling with those moms except with his exwife that he deeply love, unfortunately shes too much to handle for him so he let go as shes independent and strong minded..he met me and he thought asians are more submissive.. i have to admit i was naive but i learned quick.he married me not out of love but to settle down as hes sick of being alone and the thought of growing alone worries him. he hardlyknows me, havent even met my family, and i havent even met his.how do you love someone you only dated twice? my common sense was screaming at me but i turned deaf to its call.
imstaying for all the wrong reasons.. but i dont know how to get out..