I think that, without the larger social and cultural structures that people call "patriarchy", it's incorrect - mostly connotatively, but it's a denotative inaccuracy too - to call any given private relationship "implicitly patriarchal". It would be like calling the relations between an officer and soldiers in a modern army "implicitly fascist".
Meaning that even if superficially there's a lot of similarity (e.g. if you provide financial support and it is understood to "entitle" you to companionship, you engage in d/s play on an emotional/intimate level, you're counted upon to make decisions, etc), it's still a perfectly voluntary, healthy relationship, absent some latent psychological issues or hidden manipulation. After all, your girlfriends wouldn't be shamed, coerced or economically pressured if they decided to break things up or reevaluate the power balance - so there's no "-archy" at work.
I'm only saying this because I also think that power play is a healthy and important part of most people's sexuality, so it would be good to define it correctly, not letting... anyone frame it as immoral/pathological/inherently abusive.
You are ignoring the much of classical New Left thought in this response. As an exercise put on your Gramschian glasses and consider how in a personal relationship based on informed consent, mutual satisfaction and without much support from the rest of society patriarchy exists in a meaningful sense. Bonus points if you see how even with the first two conditions in place this might be something feminism and regular Joe would strongly object to.
I skipped October and November owing to election season, but opening back up:
As Multiheaded added, "Personal is Political" stuff like gender relations, etc also may belong here.