Despite all these conditions, still believer couple do get lot of divorces as well which has nothing to do with both of them having same beliefs.
Marriage is a very complicated system. it can be simple only if you want to make it else let alone it will have its issues over the years.
Most of the folks in practise look for other attributes like wealth, fame, social status, beauty, religious beliefs are not any more relevant.
We can talk about all day but at the end the most important aspect for couple to marry is Love which can not be defined by any statement. It just comes out of no where and consume the lovers.
Yes.. Fusion
That's world life...
Successful marriage life and those who allowed or recommended to marry are two matters...
Even serious believer as end up in bad marriage life evwn with a good believer..
For example.. nonbiologoalson of Mohamed ie Zaid.. He divorced his wife.. He was a good person a believer.. And definitely his wife would have been a believer otherwise they won't marry as per conditions.. On top of that prophet won't marry Zaid's ex-wife unless she was a believer.. Believer to believer doesn't mean marriage life would last.. Even Allah warned all wives of Mohamed that He would replace them all with others...so life and love is different to believing person... God's preference is believer to believer... Love can even happen with non believer ..even may fall in love with even while one have a legal wife with another woman.. Love is not marriage..
Marriage is unique and it gives right to a person over each other.. Why Allah allowed divorce foe believers... It is not easy a successful life together.. A believing couple may fail in marriage life while a mushfiq couple may succeed beyond expectations in marriage life.. So life is different matter to what God's law...
God never said marry a mushrik if she is good and if you fall in love.. God clearly stated marrybthose who believe... That's worthy following.. Even to parents of those who expect marry God says don't give your children to.... So... If life is so important than God's law it is absolutely fine to take it.. We never know what God's judgment for disobeying his instructions... Anyway everyone get their partner somehow... And if they not intended to violate God's law while marry and if they remain believers in life time.. God is the forgiver who deserves..
2:221 And do not marry polytheistic women until they believe. And a believing slave woman is better than a polytheist, even though she might please you. And do not marry polytheistic men [to your women] until they believe. And a believing slave is better than a polytheist, even though he might please you. Those invite [you] to the Fire, but Allah invites to Paradise and to forgiveness, by His permission. And He makes clear His verses to the people that perhaps they may remember.