Please understand this, there is NO secret marriage in Islam. He dont need approval from his parents to get married, He dont need approval from his 1st wife to marry another wife but "at least" inform her that he is getting married a second wife and the least thing she can do is ask for divorce. Now, if he is telling you that he wants to marry you but his parents DISAGREE about it then is obvious that he is "cheating" on his wife and "playing" with you?

A Muslim man can marry a Muslim girl, a Christian and a Jew. Requirements as follows:
1) There is consent of both parties
2) There is consent from the parents/guardian of the GIRL, a father or an uncle or brother, but since you are a reverted Muslim then the judge himself can stand as your guardian.
3) There are 2 male witnesses or equivalent to 4 female
witnesses.
4) There is Mahr or Dowry for the bride.

The requirements never mentioned that you need consent from HIS parents. Which clearly means he is lying on you. Do you know that he is married with one kid before you indulge into relation with him? If YES, then shame on you! If NOT, then shame on him not to tell you the truth. Wake up girl!