One possible link between monasticism and communion.

The sacrament of communion makes you one with God through the implicit flesh and blood of Jesus.

Sexuality with the one you love and who loves you makes you one with that person in flesh, blood and spirit. The element of spirituality in this oneness is a basic human urge and it is only dilutely expressed in phrases like 'my better half.'

Abstaining from sex gives the opportunity of attaching this spiritual yearning entirely to God and becoming a 'bride of Christ.' This used to be said about women going into nunneries, but I think in these days of gay marriage it can just as well be said about men. After all, there's no actual sex involved, just a huge spiritual hug. Thus monasticism becomes another form of communion. Specifically, a marital form of communion.