Hero is definitely the character who best exemplifies a Christian spouse. Hero is modest and loving while Beatrice is known for her antagonism and pride. Hero is very forgiving while Beatrice desires to seek revenge.
We see Hero acting modestly on several occasions. At the masquerade ball, when she is asked by the masked Don Pedro to walk about with him, like a modest maiden, she demurely refuses, saying, "So you walk softly and look sweetly and say nothing, I am yours for the walk; and especially when I walk away" (II.i.74-75). We see her acting modestly again when asked if she will participate in a plot to trick Beatrice into falling in love with Benedick, as we see when she replies, "I will do any modest office, my lord, to help my cousin to a good husband" (II.i.329-330). A third time we see her act modestly is when she shuns Margaret's sexual joke concerning the heaviness of Hero's heart, "'Twill be heavier soon by the weight of a man," with the reply, "Fie upon thee! art not ashamed?" (III.iv.24-25). In contrast to Hero's modesty, Beatrice is very antagonistic and prideful, which we see when we witness her openly insulting Benedick and challenging his wit. We also see her being prideful when she openly rejects the thought of ever having a husband.
The second attribute of Hero's that makes her an ideal Christian wife is her ability to forgive. After she has been publicly slandered by both Claudio and Don Pedro when she is innocent, all we see her do is plead her innocence and question his sanity, as we see in her line, "Is my lord well that he doth speak so wide?" (IV.i.59). After the accusations are over, she never expresses anger at either Claudio or Don Pedro, she merely tries to defend herself. When Claudio finally understands that he was deceived by Don John, Hero carries through with the second wedding and even proclaims herself to be born anew. We see her proclaiming her rebirth in the lines:
And when I lived I was your other wife; ...
And when you loved you were my other husband.
One Hero died defiled; but I do live,
And surely as I live, I am a maid. (V.iv.61-66)
It is her ability to forgive Claudio for his actions that allow her to be reborn anew and continue her wedding with Claudio, showing us just how much Hero exemplifies a Christian wife.
On the other hand, Beatrice demands that Benedick avenge her cousin by challenging Claudio's life. Beatrice's desire for revenge shows us that she is not a model Christian wife while Hero is.