M28 F45 Bf keeps letting and hiding communication with female coworker

Relationship advice

My boyfriend and I have been together for about 5 years now. When we first started dating, he would have this coworker that he’d text outside of work and even had her on Snapchat. They became friends but he became too friendly (texting good morning and asking if she would like any breakfast otw to the office), I told him I didn’t like it and so he changed her name to a guys name but I found out. He ended up leaving that job during COVID.

He landed a new job and again, he became close with a female coworker. She is much older than him, we are both 28 and she is about 45. He says there is nothing going on. I believe it but they started texting and talking on the phone after work hours and even late in the evening. One time, she texted at 11pm then called another time around 9:30pm. I addressed it and told him there needs to be boundaries set and at first, he was very defensive and claimed there is nothing going on. I explained that it is just weird calling and texting an older lady from work like they have known each other forever. He claimed he would limit communication and keep it strictly at work.

I caught him deleting her text messages and call logs from a weekend I was away on a trip. He again claimed he would stop but felt the need of texting her again on a weekend late around 9:30pm about a game, it was just a comment and she responded telling him he’d get in trouble. Obviously she knows it bothers me that they talked so much. He then said ok, this time for real I am not talking to her outside of work and keeping everything work related. He started using teams and chatted with her constantly about work and non work related subjects.

I think he should have mentioned this communication channel because if there is nothing to hide then he should be open about it and not be having secret conversations with this woman. Am I over reacting? I’ve set my boundaries and was open about how I feel about their relationship but he continues to break these boundaries, lie about not keeping communication with her and continues to delete messages. Should I just ignore this weird relationship they have? I just can’t continue having this conversation with me. I am repeating myself every week so he can understand but he thinks he is not doing anything wrong.