So my boyfriend (26) M and I (25) F have been dating for 8 months. Throughout the entire duration of the relationship, I suspected him of having a crush on his coworker/best friend who is a female. They have been friends/coworkers for around 2 years. She is his boss and they are alone together at work for 5 hours and they are very close and talk about everything, including his relationship with me and her previous relationship. She is currently single and has been for a few months now. I have talked to him about my gut feeling of him having a thing for her, as they have the same interests and hobbies and get along really well and physically he admitted when I asked him if he thought she was pretty, he said he did find her pretty and attractive when they first met. He said he never had a crush on her and I just can't find it in myself to believe it at all. He said to me if he wanted to be with her, he would be and he chose to be with me. They text frequently as their conversation is always at the top of his recent texts and snaps. She had a health monitoring app that alerted her phone that he also said he installed. When i asked why his phone was being blown up by an app but he explained it to me and said he installed it due to a joke. I told him it was weird for him to be alerted of her health and I didn't like it and he agreed and uninstalled and told her about him thinking it wasn't right. She then messaged me saying all of her coworkers are also notified and she didn't mean any harm. I've been feeling suspicious and my gut feeling has been telling me he is lying to me about his true feelings for her although he's reassured me multiple times that he doesn't and never has seen her that way. It's wrong to have felt this way through the whole relationship but he hasn't done anything to break my trust as of yet. Also to note he does not hang out with her one on one outside of work except for when they occasionally game together online. Should I trust him or should I end things because I always have a gut feeling about him having feelings despite being reassured he doesn't?