Married to an alcoholic

Hi,i am 28 yrs old female....i am married for the past 10 yrs,got 2 daugters.mine was a love marriage...my husband is now an alcoholic.....i was working but my husband is very suspicious so i had to quit my job...i m fully dependant on my husband...want to leave him but can't
i am also having an affair...this guy is working in an mnc in a good post...he loves me n is very possesive...i want to get married to him but can't....his family will never accept....
i m worried...this other guy will get married some day n then i will be left alone.....i m getting irritated....feeling sick....can't expect any kind of emotional help from my husband though every1 says he loves me a lot....what do i do?what is correct for me plz advice....i m tensed about my daughters future...will i b able to be a good mom to them?or will they also suffer like me?