Let us say that your daughter married a lousy man, who decides up to and leave her and run around with the dames. And then, one night, a few months later, he shows up on her door step in the rain asking to come in. And your daughter asks him, "Are you back for good?", and he says, "No, Betty and Jane and Angela were all busy tonight. I'll be back with them tomorrow, but I'm here now, let's enjoy the night."
Would any of you want your daughter to open the door, or would you rather she slammed it in his face?
Ladies and Gentlemen, this is why we have closed communion.
When a person is confirmed, they are asked, "Do you intend to continue steadfast in this confession and Church and to suffer all, even death, rather than fall away from it?" Likewise, when a person is married, they are asked, "will you keep her in sickness and in health and, forsaking all others, remain united to her alone, so long as you both shall live?"
Both are intended to be lifetime commitments, not something you just flirt and flit into and out of on a whim. As we would know that it would be wrong to encourage the scoundrel male in the example above, likewise, we ought not encourage people to be dismissive of their Confirmation vows in how they practice communion.
And you realize, this isn't a stretch. Consider: "For no one ever hated his own flesh, but nourishes and cherishes it, just as Christ does the church, because we are members of his body. “Therefore a man shall leave his father and mother and hold fast to his wife, and the two shall become one flesh.” This mystery is profound, and I am saying that it refers to Christ and the church."
The analogy is most appropriately applied to communion, because the Sacrament of the Altar is the higher and greater mystery to which marriage points.