Got remarried and I took my boys to visit there father and he raped me dna test are going to be done on my one in half year old twins but my husband is on the birth certificate what rights does he have if they are not his?

Need to know where you live, also did you file rape charges against the father to document the rape ( not merely agreed to sex)

In many areas if you are married, the husband is considered the legal father unless there is a motion filed for paternity.
The time to file differs greatly by location.

But in general if he does not object he will be the legal father with all rights and responsibilities.

Got remarried and I took my boys to visit there father and he raped me dna test are going to be done on my one in half year old twins but my husband is on the birth certificate what rights does he have if they are not his?

It depends on your state;s laws.
For example-if you are in Tn, your husband's name will be removed immediately from their birth certificate and your ex-husband will become their legal father with all rights and obligations.
There are 2 year statute of limitation for establishing paternity where a child/children are presumed by marriage to be husband's .It is true for La.
... AND SO ON.
We need to know your location.