Marriage

Islamic marriage although permits polygamy but it completely prohibits polyandry. Polygamy though permitted was guarded by several conditions by Prophet 

can you explain clearly..and know me what are advantages & problems with this?

please let me know all about islamic divorce and second marriage and what are the rights having first wife 7 Second wife..

Under the  specific circumstances, the Qur'an  recognized that if a person feels that he shall be in a better position to meet or fulfill his social obligations (example: towards the orphans), by marrying a second wife  (the mother of the orphans), provided he can deal with his wives in a just and equitable manner then he may marry the woman (example:the orphan's mother ). The Qur'an  does not hold the consent of the first wife of the person as a mandatory requirement for a second marriage

Ok..but his wife puts section 498 A  and other cases on him.. in this time we both can marry or not..? if we marry leggally we face any problems in muslims? Please clarify..?

You can marry that muslim person during the subsistence of his first marriage but before marrying him, you should convert into a muslim. Once converted, he is eligible to marry you as his second wife which is permitted as per muslim personal law.  The impending 498a case is not a bar for this second marriage.