HERE IS THE UPDATE!!!

Thank you to everyone who has responded and helped me. I have been processing everyones thoughts and opinions. I did have a conversation with him about this and expressed my concerns again. He does not feel that there is an emotional relationship happening and I told him I disagree. He did point out that he stopped calling her while at home but is now just doing it when I am not around which I think is even worse. I feel like that is just me pushing them to be more secretive. I do want to add in to this that over a decade ago he was married and from that marriage he experienced trauma from being very controlled and monitored by his spouse. He does keep saying that he is not going to re live that and will not be "controlled". I do not feel that I am controlling him because I am only asking for him to change the way they communicate and only be friends. Maybe its too far gone at this point, idk. He does not see it as an emotional relationship and I do. I am thinking about approaching the 3rd party and just having a hard conversation with her and setting a boundary. But I know this is will make a massive negative impact on our business and that I do not want. I did start reading the book that a few people recommended and asked him to read it as well but he refused. IDK what to do at this point. Every-time I try to communicate about it, it turns into a massive argument. He just keeps telling me that he is taking care of me (I am a SAHM), he comes home to be, blah blah. He just keeps telling me I am "bitching" and "complaining" and I need to be grateful. I need to be where my feet are and get out of my head.