Friends first, usually
Aries and Aquarius often begin as friends, or as two people complaining about the same thing at the same meeting. Each is allergic to being told how life is supposed to go. Aries pushes against rules by simply ignoring them. Aquarius has a whole theory of why the rule shouldn’t exist. Together they tend to be good company, and a bit of a handful at a family dinner.
Their shape as a couple might not look like anyone else’s: separate friends, odd hours, unusual living arrangements. If it suits them both, it’s nobody’s business, and they tend to be good at ignoring those who think otherwise.
Heat against distance
Their fights have a particular shape. Aries gets angry fast, and in person. Aquarius goes cool and reasonable, and starts talking as if the two of them were a case study. To Aries that’s maddening. They want a reaction, and they’re getting an analysis. To Aquarius, the shouting feels like a loss of basic good sense, and they may walk off to think.
Under this sits a question about priority. Aquarius gives time freely to friends, causes and strangers online. Aries likes to come first, and won’t always say so in as many words. They may just pick a fight on the night of Aquarius’s group thing.
What keeps it warm
Keep one regular thing that’s only the two of you, so that all that freedom has somewhere to come back to. Aquarius can say “I feel” before saying “I think”, even when it’s uncomfortable. Aries can try saying “I miss you” instead of starting an argument, and give Aquarius a little time to come back round before expecting an answer.
Do your charts have warmth to spare? Sun signs don’t say. Venus and the Moon do, and two independent people often have more tenderness to share than their Suns suggest.