Think about why Dale Carnegie's book became a best-seller.
Hint: huge numbers of people don't feel the need to buy a book about how to act a certain way if it came naturally to them. They would just act that way without need of a self-help book. Therefore, it stands to reason that the book is pushing a way of behaviour that does not come naturally to many, many people.
I read a book a while back - for the life of me I can't remember it's name - that discussed the history and styles of self-help books. What is considered the 'right' way of acting and behaving has also changed over time. These concepts have fashions, too, and are not indicative of a deep and universal truth about what is the 'right' way of behaving and interacting. Before the Dale Carnegie type books it was books about doing your personal best, and being quiet about one's own accomplishments. Nothing about being out-going or social at all, quite the opposite in fact.
Therefore, in my opinion, better to concentrate on what works for you personally than what a book tells you about the 'right' way of behaving.
My son has an ASD diagnosis.
After a lot of reading at the time of diagnosis (and since), I'm pretty sure I have it too, and most of my relatives as well. But no official diagnosis as we grew up at a time when it wasn't recognised. So I understand well the feeling of not getting things right socially.
On the other hand, with increasing age, I realise how arbitrary and unfair most social rules are, and truly just don't care any more about trying to follow them.
Based on all of that, a few questions:
-why on earth be a social butterfly, unless that is something that makes you happy?
-do you have any friends (even if just one, and even if it was in the past rather than the present) where the friendship does not feel like work? If you do/did, THAT is what friendship should be like.
-you have a good job, a marriage, and at least one child. How do you think you would feel if you concentrated on the positives in that and how it reflects (positively) on your life up till now, instead of looking at how you think you 'should' behave?
-what makes you happy? If doing those things or being like that doesn't hurt anyone, then concentrate on them rather than how you feel you 'ought' to be doing things.
-does coming across as 'rude and stand-offish' affect you, your career, your husband, your child, to a significant extent? If it doesn't affect it, try to accept yourself as you are, rather than trying to make yourself something you are not. If it does have an effect, work on changing yourself only to the amount that is do-able for you.
Be kind(er) to yourself. 