Regulus
Regulus Black knew better than most what it was to be loved by James Potter. And knew better than most how easy it was to love James Potter.
Regulus loved James because he was everything warm and bright. Because he became the bright spot of Regulus' life.
And Regulus loved Remus in his own way too. Remus who was his solace in the Marauders group. His escape from the louder tendencies of the group. Regulus found loving Remus only natural when he was around the group more.
Regulus prides himself on noticing more than most. On constantly observing those around him. So he had noticed that James and Remus were friends. Had noticed that at times they were very close. Logically the connection between that and how individually lovable both people involved were should have been an easy one for Regulus. But he had honestly not really thought about it. By the time he was dating James, James' relationship with each of the Marauders was well established and unique.
But there were times when his eyes caught on the pair for longer.
Initially, before he was dating James but after he had reconciled with Sirius, Regulus noticed how they cared for each-other over meals. Regulus was struggling to feel totally comfortable sitting at the Gryffindor table, but his brother had asked and Regulus could not say no. So Regulus, as often as he could slip away from his friends, would sit with Sirius. Later in their years his friends and Sirius' would all sit together but that phenomenon did not exist yet.
Every single meal time Regulus would watch James and Remus play their strange little game. The game in which they would sneak extra food onto each-other's plate every time the other person turned their back. The strangest part being they both did this, and neither noticed. Some times of year it would be a more aggressive game. Around full moons (Regulus would later learn why) James wouldn't even try to hide his food offerings. Just steadily piling up Remus' plate, always picking Remus' favourite foods. During particularly stressful exams or assignment times, Remus would take this role and blatantly push food onto James plate.
Watching at other times he noticed that both of them seemed to have problems remembering to eat. And that without this little game, often both of them would not eat enough in a day. Especially when they were stressed or tired.
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For Regulus, the strangest thing he learned of the way James and Remus cared for each-other was through reading. It was one of the first things that had formed the bond between Remus and himself. Because of this, Regulus knew Remus' fierce love of reading and that Remus' happy place was a book. At any and all times he could be relied upon carrying at least one.
James however? Not such a reader. He's smart, wickedly smart. Smarter than most people ever realise. If it were just about the keenness of his mind, his constant curiosity, he would be a veracious reader. But his attention span, his need for movement, never allowed him such peace as settling down with a good book. Regulus couldn't love him any less for it. He put up with every ranting session Regulus wanted to go on about his current book. It was just another part of the wonderful human that was James.
So perhaps he is surprised when, one night in the common room when they're all lazing around on the armchairs, Remus finishes his book and tosses it over to James who catches it easily. No words are exchanged. James just starts reading the book from the beginning.
It happens again and again. Every book Remus finishes goes straight to James. And James reads them. Every word, every page. Usually while walking between classes, or between drills at quidditch practice. He doesn't stop moving, but he reads every book. And then the debates. The moment James finishes the book, he is debating with Remus about every aspect of the book.
Regulus waits until his relationship with the Marauders is solid when he asks Remus what it is about.
"You've probably noticed that our group aren't big readers. Sirius puts up with it but has no real interest in reading. Peter reads completely different genres to me and isn't really up for talking about it. Until you came along, no one really wanted to talk to me about my books. But I noticed that James would always be willing to listen to me talk about them. Plus he is a great debater on topics he knows. So I picked a book I had just read that I wanted to debate about, and asked him to read it. He's a softy that boy. Someone he cares about asking him to do something is pretty much ordering him. He read the book in like two days. In his strange way of reading. Then he came to me the moment he finished it and we talked for hours. He seemed to love doing it, so I kept going. Now it's expected. He would take the book if I didn't give it to him." Remus explains.
Regulus loved James just that bit more after hearing all of this. Because he really is a softy who would do anything his friends asked. And Remus knew James well enough to engage him in these books without the pressure of having to sit down for hours and read them.
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The most obvious signals of the love between James and Remus is something Regulus only gets to see a few months into dating James. Something the Marauders seem to keep private from the world.
Both James and Remus, at different points in time, experienced a kind of sensory overload. A point in time in which every sight, smell, feeling, taste, and sound become far too much for them to handle. Peter and Sirius have seen it many times before. So when it happens, Sirius explains it to him while watching worriedly from a distance. It plays out a pretty similar way each time.
Often they seek refuge in their dorm room. James seems to take the most comfort from having his head pressed into Remus' chest with Remus' hand covering his exposed ear. For James, the first sense to stifle is sound. The others take time but sound is the first one he needs back to recover. Remus becomes a muffling charm for James, filtering out an unnecessary sense in order for James to take time to recoup and recover.
Remus seems to take the most comfort from having his face pressed into James' neck. For Remus, the first sense to stifle is sight. The bright lights or sudden movements of the world around him and the first things to remove. James knows to draw the curtains around the bed and tuck Remus into his neck. James knows to act as an eye mask for Remus.
When the world is overwhelming, James and Remus find solace and comfort in each-other.
This seems to be the best way Regulus could explain the love between James and Remus. Because that's what it is, love. James and Remus are each-other's solace. Each-other's protector. Each-other's wellness check. They always have the other in their mind and always check on them.
James and Remus do not love each-other loud, or predictably. Their love is quiet. Their love is solace in a storm. Light in the dark. It does not announce itself, or force itself upon you. It is a precious kind of love that Regulus feels privileged to see. Feels overjoyed to know that two people he loves are so loved. After all, the quiet is when people can be the loneliest. Quiet is when one needs the most love.