I think for me my answer wouldn't answer your question, which seems to be more "who can you turn to and rely on?"
I have a few people who I believe love me as best as they're able, but I've been raised and trained to expect and ask nothing of people and to accept versions of love in which mutual support just doesn't exist.
My DSIS and DF are the key people I'm talking about. I know they love me, and they would both say I could ask them for anything, and in practical terms (mainly money, some logistics, but they'd prefer to contribute money to help pay for the logistics) I know I could. But real, emotional, I feel your pain and I'm here for you emotionally support - they just can't. They can't either give or receive that. They just don't know how. Classically I have ended up for a man very like my father - emotionally illiterate, very clever, very hardworking, will do anything practical for you to sort out problems but would rather be dragged over hot coals than talk about feelings, mine or his. It's not the worst thing a man can be I suppose (some of the lazy mean abusive arseholes I read about on MN have made me realise that) but for an empath and emotional incontinent like me it makes for a very lonely life.
My DM I know loved me in a powerful dramatic way. But I also know that she had an idea of the person I was in her mind (basically an idealised younger version of herself) and when I evolved and changed and stopped validating all her self-destructive, selfish behaviour she cut me out (until she realised she still needed access to my financial support). But for years, when I was who she wanted me to be, we had a very close, almost romantic love between us, she let me in and allowed me to support her, relied on me, and now she is dead and I don't have that with anybody else I feel bereft.
My DStepmum is different and I'm lucky to have her. She is emotionally articulate, practical, occasionally wise, and would do anything for anyone. She's not perfect, who is, but I love her for being "normal" and sensible and for loving me (in a warm, brisk, wholesome way) when she has no obligation to whatsoever. Until I wrote this down o don't think I realised how much I appreciate her.
I ought to love my D-half-B and I do, sort of, but... We barely know each other. He's 9 years younger than me and had a totally different family environment, we don't have any shared frame of reference and he's a young man busy with his own life. But there's a good base of good feeling on both sides that I hope one day when our lives are more aligned we will build into love. We always get on like a house on fire when we do meet. But I'd no more turn to him for help than I'd turn to an acquaintance at work.
But my true love, my utter passion, the love that made me review all my other loves and reluctantly downgrade them by comparison, The Real Thing is my DD. She is EVERYTHING to me and I'd die for her without question. No-one else in the world is as beautiful, funny, clever or worthy in my eyes. It's all biology I know but nonetheless. I didn't realise before becoming a parent that love could be so huge and straightforward. How she feels for me I think now is love (she's 2). If I can hold onto her love in some form of think I'll always be happy. But I want her to have a sibling, because this love of mine is too huge for one person and I never want her to feel smothered or obliged.