Help and advise needed.

I am a 54 year old father of two with a loving wife. I have struggled with my traits since I was a child. 
I can start with childhood, I never had friends. I always wanted to be on my own I thought it was normal. I was in top sets for English and Maths but was taken out of lessons as I was quiet and didn’t join in. I never joined in with the crowd. I was put in a class of 4 about twice a week and given a tambourine! This was the 1970’s.
I have always preferred to work on my own as a classic car restorer, I’m always being told how excellent my work is but don’t see it myself. My attention to detail is always commented on. I  found lock down a gift as no one could visit. 
It has almost become a joke with others that I never answer my phone, I can’t it makes me very anxious. 
I had to go to a restaurant a couple of weeks ago, the thought of going anywhere has always been an issue. I would rather start an argument so I don’t have to go. 
My wife comments,” I suppose we will have radio silence for 2 days” this when I stop talking for the days coming up to an event and withdraw into my self. She gets very fed up with going to events on her own.
My wife will sometimes ask for a cuddle, I will put my arms around her and all I’m thinking is please let go of me. 
I have two wonderful grown up sons, one is 24 and the other is 20. I was able to cuddle them when they were small, as soon as they became “ people “ I have never been able to humanly touch them. 
I saw a customer a few weeks ago with his arm around has son having a joke, I thought why can’t I do that?  
I drank a lot of alcohol one night last week and then broke down and told me wife everything that I have held back since we were teenagers. She now knows why I’m like I am. It becomes an easy thing to shield others from after a lifetime. 
I thought I would speak to my mother so I sent her an email as I find it easier, I told her that I think I am autistic. She came to my workshop the next day. I think she thought it was an attack on her parenting skills, her generation see most things as black or white. I got comments of you can’t be autistic, they are people who don’t talk and stare at the wall. I asked her why didn’t she notice  I was different at school? 
The answer was, “the school just said you was quiet “ I now feel it’s like  I’ve been playing a game of snakes and ladders and just gone down the snake back to start. I know I’ve got to summon up the strength now and go to my GP, he is a new one as my old one of many years has retired. That is the next hurdle. I’m not after a cure, all I want to know is why I’m like I am? It wasn’t till I told my wife who is a long serving nhs nurse that the penny dropped, why didn’t we think of autism years ago. It has taken a lot for me to post this. It is only a small part of how I’ve felt since childhood.
 I just want to know if anyone else out there feels the same as me? 
Is it possible to live for over 50 years without knowing why I’m different? 
Any help would be great.