I tend to feel I may be rather emotionally detached from others, but I think it may be one of these things that's happening without my noticing it very much. I always used to feel I wasn't as bonded as I "should" have been with my son when he was young, but a counsellor remarked (words to the effect) that we were clearly very strongly bonded emotionally. Similarly, I've often felt rather detached from my partners but I think there's actually always been a lot there that I didn't much notice at the time.
There are a lot of different definitions of human connection out there, presumably because it's a very subjective thing that's hard to pin down. Most of the descriptions are about partners. They try to detect it with questions such as "Do you have each other's attention when it's wanted?" "Can you comfort each other when one of you is upset?" "Do you care about each other's well-being?" "Do you value each other's opinions?" "Do you boost each other's self-confidence?"
Signs and causes of lacking emotional connection are said to be such things as being too busy to pay attention to each other's feelings, being unwilling to open up emotionally, failing to communicate emotions to each other, failing to do shared activities together.
I think I score reasonably well on most of those things. One shortcoming is that I can't easily be consoled if I'm upset or anxious about something - it seems that only credible information about how to fix the cause of the upset, or about why I might be overestimating how bad it is can soothe me. AFAIK, pure "emotional support" doesn't help me, though I'm not so sure it truly doesn't help me. Sometime I've felt strangely empty and it's only by thinking that I've begun to see that it was probably because somebody I felt rather attached to had gone away, and even then it's only been a theory, I haven't known it was that. I've had conversations after which I've felt emotionally wonderful, truly nurtured. I've known it was something about those conversations but I'd have difficulty in describing it very clearly.
I can certainly feel sad when I'm separated from people I'm close to, and I suppose that's an indicator that I miss them, but it's hard for me to name it as missing them. Similarly when I learned that my father was dead, I wasn't aware of any grief about it, and wondered how I could feel so cold-hearted, but after a few minutes I suddenly felt that all the colour had gone out of the world around me. Looking back, of course it would have been emotional pain at losing somebody I'd bonded with very strongly and for many years when I'd been a child.
So maybe it's "all there" really, but with ASD there's often this alexithymia thing going on, which isn't the inability to have feelings, it's the inability to name them, to know what we're feeling.