Is it a cybercrime if I took screenshots of wife's whatsapp msgs to her boyfriend?

Hi, Wife had a boyfriend & they used to chat using Whatsapp messenger. 1 day I took her phone without her knowledge, used Whatsapp Web option and logged in to her Whatsapp number from my computer browser. I took screenshots of a few Whatsapp messages she had sent to her boyfriend. I did not export or archive those msgs. I just have screenshots showing her boyfriend's name and the msgs they exchanged for a few days. 2 months down the line, Wife & I had a heated argument on this issue. I showed her all her msgs. She left my home & filed a false Domestic Violence case. She has mentioned that I've hacked into her whatsapp/email several times and I should be punished as per cybercrime law. Questions 1) Can I make use of those screenshots to prove her adultery? 2) Is it really a cybercrime to take screenshots of one's private chat with someone else? I understand it's intrusion of privacy but my life is at stake here and those dirty messages between wife & her boyfriend are my lifesaver. In cricketer Mohd. Shami's case, his wife took photo of the messages he had sent/received from another girl without his knowledge. Mine is a very similar case. But I think I scored a negative point since I used wife's phone to explicitly login to her Whatsapp account from Web without her knowledge and took screenshots of her chat with a 3rd person. 3) If I write down all msgs on a paper & show it as proof in court, will it save me from cybercrime offence? I know it's a foolish question (coz you may say I can write anything and pass it as something written by her boyfriend on whatsapp). But I really want to use those messages. I am desperate. Please help. --OIBM