Akihiko is Haruka's first love - at first a slow-paced relationship, due to their mutual teenage awkwardness, some burdens of the past, and end of the world shenanigans, she eventually fell head-over-heels for the guy after he gave her a stupid ass bunny doll. Love is strange, and that's why as a couple, they have a strict no-bullshit policy, backed up with his personal promise to protect her, even if she doesn't think she needs it. As such, Akihiko is one of the few people that Haruka will show a vulnerable side to, and she appreciates that more than she could ever have realized. When they're together, Haruka feels like the luckiest woman alive. Especially when she thinks about his sweet ass. Aww yeah.
[ S. LINK ] Rank MAX [ ARCANA ] XVII. The Star
JUN ARAGAKI
[ PERSONA 3 (OC) ] "No matter what, Haruka, you're the best friend I have."
Oh, Jun. Where would Haruka be without her? The answer, of course, is up shit creek without a paddle, but we'll expand on that. Jun is Haruka's childhood friend, and the two couldn't be more opposite. While Jun values Haruka's honesty and loyalty, she in turn values Jun's friendliness and advice.
[ S. LINK ] Rank 7 [ ARCANA ] X. Fortune
SHINJIRO ARAGAKI
[ PERSONA 3 ] "Knock it off. Haruka's just an idiot."
Haruka and Shinjiro are not particularly close, each preferring to spend time with their best friend or significant other, and so they haven't really spent any time alone. However, there is an unspoken mutual understanding between them that mostly stems from Shinjiro's appreciation of Haruka for being there for Akihiko, which of course manifests with buckets of sarcasm. He is Jun's husband and Haruka considers him extended family, but they are content with the relationship as it stands.
[ S. LINK ] Rank 1 EXTRA [ ARCANA ] XVIII. The Moon
(code borrowed without permission from evokethefool!!)