Of course celibacy is an alternative to marriage or fornication. Just because you may not prefer it doesn’t mean it isn’t an alternative.
The point is and remains, one does not get married to be celibate. That is not God's intention. Sex within the construct of marriage is, and always was intended by God to be a beautiful thing, designed to draw man and woman closer.
When one partner decides to unilaterally stop what God designed, that IMO is a violation of one's wedding vow's and frankly, means the marriage is over.