it seems like society has engineered itself into a real pickle as evidenced by all the hand-wringing articles on this topic.
personally i find serious relationships to be a giant waste of time, probably because i'm no good at maintaining them or i just don't check all the boxes, or whatever. i like dating and commitment-free sex, so i really don't have much incentive to improve. i'm basically financially independent so i don't really care about paying for things most people would split. in the few instances i've sincerely tried to keep it going, it ended after no particular incident/fight/whatever. just fizzled out, or a non-dramatic breakup over text message, which doesn't really bother me. these things come and go and i have no real hangups about attachment or have any dependence issues.
personally i think there is no "fixing" this, at least for 20 or 30 years until a brand new generational cohort come into their 20s and 30s. non-immigrants are simply just going to get married less and have less children than were historically 'normal'.