Protect the sanctity of marriage by protecting it from government interference.

Redefine the legal partnership between two people in the eyes of the Constitution as a civil contract, and let the term of loving union between two people be decided by themselves and their belief.
We are at a point of social evolution where on this matter we can neither strip religion of it's constitutional right to deny the validity of a same sex relationship, nor deny same sex partners the Constitutional right to be equal in the eyes of the law to those with religious beliefs.
Based solely on the Constitutional separation of Church and State the religious based description of a legal union should be abandoned by Congress in favor of a legal description for its legal union, and that legal union should not discriminate against any two people from entering in for any reason.