the case of marriage between a tribal with a non- tribal the main factor for consideration is whether the couple were accepted by the triable society to which the tribal spouse belongs. If he or she as the case may .

be accepted by the society then their children shall be deemed to be Scheduled Tribes. But this situation can normally happen when the husband is a member of the Scheduled Tribes.

2) you can divorce your first wife as per customary law applicable to tribals 

3) after divorce you can remarry 

You can marry another woman when you have 1 wife. There is no separate law for tribals.only if your custom allow you can marry but the same cant be registered 

When a tribal man marries a non-tribal woman, the law applicable is Hindu Marriage Act, 1955. Unless such man divorces his tribal wife, he cannot marry non-tribal woman. If there is custom of divorce under some tradition in the trine, he can divorce his wife under that custom without approaching Court. 

The Supreme Court has ruled that a non-tribal man married to a tribal woman or their children cannot claim the benefit of government ...

The transplantation of outsiders as members of the Scheduled Tribes might dilute their way of life apart from such persons not suffering any disabilities.

Marriage in tribal societies is a transaction: it is also an institution with a place in the social structure. Status in marriage is seen as a crucial issue. The movement from filial to conjugal status in a first marriage is fundamental and irreversible; it is not diminished by subsequent divorce and remarriage.

Dear client 

In India, polygyny, or the practice of having multiple wives, is illegal under the Hindu Marriage Act 1955. This means that a tribal man cannot legally marry a non-tribal woman while his first wife (who is tribal) is still alive.

If the tribal man wants to end his marriage to his first wife and marry a non-tribal woman, he must first obtain a divorce. This can be done through mutual consent, or if the two parties are unable to reach a mutual agreement, by filing a divorce petition in a court of law.

The law applicable for the marriage between a tribal man and a non-tribal woman would depend on the personal laws of the individuals involved. For example, if the tribal man and non-tribal woman are both Hindus, the Hindu Marriage Act 1955 would govern their marriage. If either one of them is a Christian, then the Indian Christian Marriage Act 1872 would apply.

It is important to note that these laws are subject to change, and it is always best to consult with a qualified legal professional for the most up-to-date and accurate information

The marriage laws that are applicable to a tribal man and a non-tribal woman depend on the location in which they live. In some locations, tribal law may be applicable, while in others, state  law may be applicable.

It may be necessary to consult with a tribal lawyer to determine the applicable laws and processes.

In case you a tribal person and your tribe is a recognised one ie by the government of India then the marriage laws do not apply to you. You may approach your community and ask for a certificate from them and take divorce.