What action can my wife take if she has returned to her parents home

The following are the legal actions your wife can take against you :

1. She can file a case under section 498 A which deals with harassment depending on how long have you been married.There are other offences she can accuse you off.

2. She can file a case for divorce against you and  can claim for maintenance.

The way you can safeguard yourself is if you wish to get separated from your wife you can file a divorce case before she goes ahead.

Else if you don't want a divorce you can file case for restitution of conjugal rights.

Assuming you are hindus,

You can file a case under section 9 of the hindu marriage act which deals with restitution of conjugal rights.

Section 9 of the Hindu Marriage Act 1955 has been explained below for your understanding:

Section 9. 

Restitution of conjugal rights - When either the husband or the wife has, without reasonable excuse, withdrawn from the society of the other, the aggrieved party may apply, by petition to the district court, for restitution of conjugal rights and the court, on being satisfied of the truth of the statements made in such petition and that there is no legal ground why the application should not be granted, may decree restitution of conjugal rights accordingly.