-Because you have got the green card more than 5 years, your US citizenship application has nothing to do with your ex-spouse.
The only question is that: did the immigrant court/judge cancel your removal proceeding before you got your 10-year green card? If yes, then you will be fine to apply for the US citizenship, and do not need a lawyer. Otherwise, you had better not apply for the US citizenship and had better consult a lawyer if you want to file N-400.