My primary partner and I have different outlooks on marriage, and I'd like to get to where he is but I'm not sure how.

I am in a hierarchical relationship structure (poly from day one), we've been together for 3 years and we plan to live together. Neither of us want children, and we are both open (theoretically) to other relationships becoming as entangled as ours, although realistically it seems unlikely, and currently we both date within our capacity - so his other relationships tend to be much more casual, and I'm currently polysaturated at one as I'm overwhelmed with my everyday life commitments (we've both been very careful when dating other people to be clear on individual limitations, I am still friends with everyone I've dated (and some of their partners) at the same time as our relationship, and he has maintained another relationship since before we met that has always been a comet relationship and has not been impacted by our relationship).

I understand that marriage would create an additional level of hierarchy that I don't actually want - I'm more "I'd rather have two spouses and split my time between two homes or cohabit if they had a genuine friendship outside of my relationship with either of them", because I see it as a primarily romantic commitment, and I'd be perfectly happy for neither "marriage" to be actually legally binding (so a ritualistic/symbolic event).

My partner is indifferent to marriage (legal or symbolic), so for me it would feel pointless to do anything symbolic as it would be onesided. But I guess my Catholic, amatonormative upbringing coming through. I've read stepping off the relationship escalator, but I'm looking for anything else that can help me break down the sentimental attachment to the idea.

Thanks in advance!

(Edit due to the bot comment - I have read The Ethical Slut, Polysecure, The Smart Girl's guide to Polyamory, & Building Open Relationships, so not looking for general poly book recs unless they go deeply into deconstructing marriage)