There is a lot of room for interpretation in both the caller's complaint AND the response. If a woman is "not in the mood" too often, then she really shouldn't be surprised if her husband finds someone who is (not that that makes it okay, mind you). However, if it is only occasionally, or if she really isn't feeling well or has had a particularly bad day, then the husband SHOULD respect that OR, in some cases, put some effort into getting her in the mood. That would be the loving thing to do.
That said, it works both ways. This line of thinking is scripturally based, but is often misunderstood. What the scriptures say is that neither the wife nor the husband should withhold themselves from the other and that their bodies are not their own. To do so leaves too much opportunity for the devil. Of course, because you seldom hear men complaining about their wives wanting too much sex, that side of it is often ignored.
Also, the Bible talks about wives submitting to their husbands, and this is often interpreted in terms of sexual matters as well as other things. This is all fine and good, but the part that is too often left out is the part that says, "as is fitting in the Lord" or "as unto the Lord." My understanding of this is that to the extent that a husband is in submission to the Lord a woman can be "safe" in submission to her husband. It is not a sign of weakness nor of inequality. Everything and everyone shines the brightest when doing what they are created to do. This is a way in which a loving God reveals Himself in our lives because He wants what is best for us, not because He wants to cramp our style.
The way this works out is that if the husband is loving his wife "as Christ loved the church and gave Himself for her" as the scriptures command, then the wife can joyfully submit herself to her husband...which might also be loosely translated as making herself vulnerable to him, because in her heart of hearts, she knows that he loves her and wants what is best for her, which inspires her to return his love to strengthen him and show him that she appreciates him. When it is in God's order, there is no higher expression of love on earth because it represents the relationship between Christ and His church.
Of course, our own will and "wisdom" often get in the way, and no expression of love this side of heaven will be perfect but that of Christ Himself. But it sets a standard and one we should aspire to in our relationships, all the while being slow to anger and generous with forgiveness, for that too is an expression of God's love.