Tammy Baldwin actually said...

the option is available for a heterosexual couple to marry, and then these employment benefits would flow automatically on the basis of that...

Should they desire those benefits, they would have the option of marrying, and that is a choice open to them.

that would require a separate act of Congress, one that I support strongly, which would be repeal of title 3 of the Defense of Marriage Act

the Federal Government cannot recognize these marriages because of DOMA, the Defense of Marriage Act