"Whoever has married has completed half of his religion; therefore, let him be God conscious in the other half" (Hadith - Reported by al-Bayhaqi)
There are abundant Hadiths (sayings of Prophet Muhammad) instructing Muslims how to enjoin good and forbid evil. However, only a few of them instruct us with explicit numbers and proportions how to behave and lead our lives. For example, while Hadiths like taking care of one's neighbors and sharing food with the poor people fall within the first general category, other hadiths, like the amount of Zakat a financially able Muslim has to pay, fall within the specific numeral category. The hadith of Prophet Muhammad that Marriage is HALF of the religion, should be understood within this context and proportionally consume half of our life to understand, reflect, and act upon.
The satisfactory completion of half of our duties, responsibilities, and purpose on earth, is NOT about going through the rituals of selecting a spouse, mating, and continuing the human progeny. While such acts are essentials, they are only prerequisites to the overall spirit of the hadith. As much as a wholesome fasting transcends the motions of abstaining from food, a nourishing marriage is the realization of the importance and active participation of the Muslims in their matrimonial life. This would obviously include fulfilling the needs and obligations towards one's spouse, children, and all those directly or indirectly related to the institution of marriage.
This Hadith draws the boundaries over which Muslims prioritize, organize, and allocate their financial, emotional, and intellectual resources. On the Day of Judgment, every Muslim will present his/her portfolio to the Divine into two equal portions; (1) The Marriage Portion and (2) The Everything Else Portion.
Assuming that most, if not everyone of us, cannot score perfect on either of the two halves, both portions will need each other to score above 50% for a favorable result (InshaAllah). Since both halves are inter-dependent, no Muslim can reasonably consider focusing on one and neglect the other. Hence, as much as taking care of the marriage institution is important (50% of our time), attempting to favor it at the expense of the other side is, from a numerical viewpoint, a guaranteed recipe for a losing destiny.
May Allah help us balance matrimonial life and the rest of our obligations, and may He bless us to qualify for his Ayah: "Thus, have We made of you an Ummah (nation) justly balanced..." (Quran 2:143)