Newbie desperate for some help with autistic wife and child

Hi,
I've been married to my wife for 13 years and I never considered she's autistic. At the same time I had very little knowledge of autism. At one stage as carer working for agency I went to support some walks and time out for teenagers / young adults that were much more on a spectrum (apologies if I don't use the correct words / jargon). 

In the 13 years we had ups and downs, I ended up losing quite a lot of money to gambling and to my family which would be abuse in any normal relationship. I couldn't understand however that my wife was upset about me clapping in the car or having a loud yawn or trying to have a bit of banter with her etc. I just came across this research Autistic Guide to Healthy Relationships - Durham University and I ended up in tears, feeling like vomiting etc as I realised how much harm and pain I have caused the woman that I love, admire and want to be happy. We have 3 children together with oldest 7 year old diagnosed on a spectrum - he does great at school, is very creative, the challenges are around eating, sleeping and sensory mainly. We have been separated for last 2.5 years, but we were still really close raising children together and apart of me sleeping some nights at different place, it was really just like it was before. 

Just recently my wife decided she wants to move on. She didn't tell me this, but she started texting / flirting on-line. I just found out about it accidentally last Sunday. She said she was just texting him for a week, but unless he messes it up, she will definitely end up at least sleeping with him. Things suddenly accelerated and she arranged a date for Friday night this week with arranging kids sleepover at one of child's friends. I found out about it from my kids on Thursday evening. As the person that was supposed to organise cancelled in the last moment, with huge pain in my heart I agreed to look after children and let her go on a 1st date. For me as a "normie" first date would be probably between 1.5-3 hours long. She has been out for nearly 14 hours now. I'm worried about her just throwing herself out there as she's in a vulnerable state of mind under a lot of pressure (on Monday after I found out on Sunday that she is texting with someone she ended up in an A&E in the evening with anxiety attack). I don't want to be controlling and I'm not in a place where she trusts me that I care about her wellbeing. I don't know what to do. Any advice would be helpful. 

She said we can still be friends etc, but she doesn't want to feel lonely. I've hurt, I really know and understand that I abused her which was never the intention. I'm so worried she's an easy target now for someone else that could take advantage of her and hurt her. How can I speak with her to encourage her to seek her happiness, but also look after her considering I love her, she said we're still friends and we're co-parents of 3 amazing young children that also need her happy and healthy. I don't want her to end up feeling really depressed and miserable, having anxiety attacks and low confidence because she got hurt by someone else. Knowing her she could go down the rabbit hole that maybe when I abused her in a middle of some disagreements and called her crazy, unreasonable, etc, I was actually right and it's her fault and she'll be punishing herself feeling worthless. Considering 13 years and number of them with trauma / being abused - I'm really worried it's unhealthy for her to move on so quickly. I kind of know it from experience as when I met her she was unhappily married and she moved with me very quickly...