Good question, I’m actually not 100% sure! This seems point to ‘no’ since its the same base spell:

https://www.dndbeyond.com/sources/dnd/basic-rules-2014/spellcasting#CombiningMagicalEffects

A dungeons and dragons term for Armour class.

It’s how you determine if an attack hits you.

Say you have an AC of 15 and an attacker tries to hit you they roll a 15 or higher with a 20 sided dice it hits you. (Meets it beats it)

However your opponent also can have boosts to to their attack say a magic weapon adds plus 1 or something so they could roll a 14 plus the 1 to reach 15 thus hitting you. Then they roll damage with another dice dependant on the weapon.

So if the characters are then married they get a plus two to their AC and now have 17 and the 15 misses

you roll a d20 (20-sided dice) to attack someone or something. if the result is equal or higher than the AC (armor class) of whatever you hit, you succeed in hitting it

It says you can’t benefit from it again unless widowed. Once someone is they can benefit from it as often as they want.

Also, you could still marry someone else and have them benefit from it again.

I mean, with resurrection being possible I think divorces would be far less often.

But especially in rich families there would probably be a lot of murdering and resurrecting, just to get out of some forced marriage.

The spell allows polygamy

Does the +2 stack in that case?

Wouldn’t the entire policule need to be close for them to get the bonus then? That doesn’t sound like the best tactical strategy.

By the way, the spell does not allow for divorce - it’s strictly “till death do us part”.

Which has… consequences

I once played a series of all-combat one shots, in which we could use the previous day to precast buffs. Every session we used that day to cast ceremony to make the party a polycule, until the DM banned it.