A no-divorce policy encourages people to think deeply about marriage and their potential partners. Since there is no way out, frivolous, ill-considered marriages are avoided. The marriage that do take place, have a stronger foundation and better prospects for happiness, fulfillment and success.
A no-divorce policy makes couples work out their difficulties rather than abandoning a marriage. That builds individual character and stronger marriage.
A no-divorce policy produces a stable long-term environment for children. A divorce is very traumatic for a child, much more than living within an unhappy marriage.
As for your points …
Abuse is a separate issue that can be handled by other legal means besides divorce.
All sorts of “loving relationships” are restricted for the benefit of society … sexual relations between child and adult, incestuous relationships, adultery, etc. There are rational reasons for these restrictions. The denial of such relationships is not in itself immoral.