Is it beginning of cheating or am I paranoid?

It's story of myself(51) and my partner, love, girlfriend who I live with for over 2 years. Let call her Jee(37). We met 3 1/2 years ago and started friendship. We were both married at that time. It developed to affair/romance and when her husband found out I decided to step out of my 25 yo marriage, divorced and start new life with Jee and her diasbled son, who I love. It was not easy, but love can carry you over anything. We both knew our past. Jee knew I had many affairs, most of them just random sex, some of them based on friendship or kind of love. I knew she had side relationship for 12 years with guy of my age, let call him Co. They were in love and they were occasionally thinking to get together officially. He was married as well, now he is widowed. At the beginning of our relationship we said to each other, we don't want to and we will don't maintain any contact with our past, as we found it as a destructive and we both wanted to make a change towards honesty and purity. "Co" contacted her from time to time. He knew she is with me, but he never cared. When I realized Jee has no guts to tell him to stop talking to her, I sent him nice polite message to explain. He replied by rudest words ever towards myself. Jee never stepped into our conversation to explain, or to show her stance. I asked her to delete his numbers (cell and home) from her cell, what Jee refused to do, so once I did it secretly at the beginning of summer 2015. At fall of 2015 "Co's" wife died. I found out about her death in spring 2016 and I informed Jee about it. She was surprised. At the end of summer 2016 I accidentally found his cellphone number in her phone. I started to be suspicious. She entered him in with fake name. I used her old cellphone to acces her emails and messenger. I knew it was not right, but I felt it's only way. I found out she knew about Co's wife since first minutes. She was in touch with him for at least month. She never told me about it as she said I would be angry, mad. I found as well she again changed his name in phone to her close girlfriend and she added there his homephone number as well. I don't know since when but at least from end of August 2016 until mid of October 2016 Jee maintained close communication with Co. They messaged themselves daily sometimes for few hours nonstop. Some days it was hundreds of messages, pictures about random things in lide. Often she texted him by sitting with me together. She constantly deleted entire conversation few times a day so I don't know all details. He called her many times to meet and she never said no. Only neutral answer even she never said later or maybe. She never mentioned myself in any way of their conversation even she talked about trips we did about food we cooked, it was always "I did" "I was". Sometimes they brought up old sex memories. It was often Jee who started conversation in the morning or after break. She sent him dozens of pictures of herself, herself with her son, food(even I cooked) or places where we were together. I couldn't hold it for longer so I came out with it and I was ready to move out. She started attacking me, laying about all. I was biggest asshole who is sneaking around. If I wouldn't do it, all would be fine as I wouldn't know. Jee still is saying it is all my fault and she can talk to whoever whenever she wants and she has her right to keep it secret. I have different opinion. She is saying she wants to be with me but I can't stand his presence in our relationship. Whatever way it is. If they would met, even for coffee I'd step out immediately. I have no knowledge about it as she was deleting constantly her messages and often the called each other as well. ...dont know what to do..

I don't see any reason for angry confrontations. She does have the right to speak to whoever she wants. She does have a right to privacy. Everyone does. If you she gives you what you need and want from her then you need to decide if you want to give that up. If not, stay and live with it and forget it (learn about compersion). If you can't live with things, just move on. No further comments are necessary. If pushed, "This isn't working for me." If it were me, I'd see if I'm providing enough for her before I decided anything.

Only thing I want is she doesn't talk to him. She asked me to do the same amd I do it. As she is saying I do more than enough for her as a partner.

One thing that is VERY clear is the fact that she is going to talk to him. You can accept that, let it be well known to everyone and hope to stop having things go on behind your back. Or you can try to stop it and fail. Or you can just go. If you decide to work through this, you should sit down and negotiate a new relationship. The previous agreement and therefore the previous relationship is broken and gone. If she can privately talk to anyone, you can also. If you want new friends, go get them. But make it clear you are negotiating your relationship and breaking the new agreement means THAT negotiated relationship is gone. Each time your negotiated agreement is broken by either party, you negotiate a new one or you move on.

Thanks ONTHEROAD. I value your comments and advices. Even it didn't bring the peace to my soul lol.

I do feel for you. You are feeling a lot of pain and you can't avoid it. I've been there. But, the sooner you realize that you can't control other people the sooner you find peace. I look at myself to judge a relationship. When the relatioship is challenging, is it helping me be better? When it is inspiring, am I motivated to pass the inspiration on? Do I have enough happy times to make life good and enough pressure to make me improve? Is there variety so that I can experience enough of life? Is my partner having a similiar experience? Sometimes, your most difficult times make your life better. I don't know if life is telling you to change youself or telling you to move on. Only you, with knowledge of your whole life, can decide that.

I wish to change myself towards better, more pure, moraly clear person. I wish to do it together with my love one. To help each other on this journey. But it must be mutual work. I wish to be her mirror and she will be mine. That was the base of our relationship. I did mistakes. And I am working on the change. It's work I enjoy as I know it moves me towards better. But I want to be better with her.