Guilt is out of place here, if it ever has a place. The nobility or ignobility of an action depends upon the motive and not the action itself. As i see it your decision to step out of the relationship was based on a rare inner clarity. It is a rare capacity to discern and I hope you will keep it in all future decisions.
Marriage is certainly not a necessity unless the need to have a child or the sexual urge is too strong in nature. It generally comes with a heavy price. Though there are beautiful moments of togetherness and the joy of happiness shared, the sense of someone being your ‘own’ to mutually take the burden and care of life, it also ties shackles to the expanding soul and often keeps one nailed to earthly needs. Very few marriages lead to a deep spiritual companionship. Hence more and more youngsters today prefer to remain single or ‘in a relationship ‘ rather than the formal institution of marriage. Commune living while staying single balances both these quite well. It keeps the possibility of endless progress open while allows us the support that a group life provides without trapping us in the net off dependency, expectations and a togetherness that is often shut off from the world and therefore selfish and exclusive.
Affectionately,
Alok Da