I said I was married in my application form to the embassy, but I wasnt really. It was a case of her having two kids for me without any real marriage legally. But at that time I thought it sufficed for marriage since we had kids together and lived together. How do I correct this problem now I want to get married to another person here? Pls reply. Thanks all.

You'd better find yourself a good lawyer. Claiming to be married when you weren't on such an application is fraud. Perhaps a lawyer could spin it as common law marriage, but then, you'd have to get a divorce from the first woman you claimed as your wife.