How is a Josephite marriage reconciled with the Biblical statements on marriage?

The practice of Josephite marriage, i.e. a marriage without sexual relations, is occasionally observed by the Catholic Church. It is modelled on Mary and Joseph's marriage and in particular the belief of Mary's perpetual virginity. I am wondering how this can be called ''marriage" given what 1st Corinthians 7:2-5 indicates about physical intimacy in marriage: > But because of the temptation to sexual immorality, each man should have his own wife and each woman her own husband. The husband should give to his wife her conjugal rights, and likewise the wife to her husband. For the wife does not have authority over her own body, but the husband does. Likewise the husband does not have authority over his own body, but the wife does. Do not deprive one another, except perhaps by agreement for a limited time, that you may devote yourselves to prayer; but then come together again, so that Satan may not tempt you because of your lack of self-control. The word translated "limited time" in verse 5 is *kairos * which would appear to indicate a limited period, i.e. not indefinite, which interpretation is also implied by the latter half of the sentence instructing the couple to "come together again." This passage would thus appear to indicate that sexual relations are a necessary part of marriage. To corroborate this, Tobit 3:8 also indicates sexual intercourse is normative for marriage: > The wicked demon Asmodeus kept killing them off before they could have intercourse with her, **as is prescribed for wives.** How are these Biblical passages reconciled with the idea of Josephite marriage?