I think I shouldn't be myself, at least not completely.

[Nobody wants Kirei to be himself. Even Kirei isn't sure whether or not he wants that.]

... I imagine it will sound quite silly to you, but I was raised to believe marriage is a sacred union between two people, indissoluble by anything except death, founded on mutual love and self-sacrifice, meant to elevate and cultivate what's best in those who are called to it, helping them grow closer to God and become more Christ-like.

[He wasn't a very Christ-like husband.]