How to handle my boyfriend’s female friend that might have feelings for him??

Can I tell if another woman had feelings for my boyfriend if I remind her that I’m his girlfriend or let her know that her behavior is unacceptable?

So my (22F) long term boyfriend (26M) and I have had some issues in the past with him and his female friends. Previously, there would be situations that turned dramatic quick and honestly if things continued to be that way I would have ended the relationship because of how stressful the drama is.

The most recent conflict we had was with a female friend (We’ll call her Dee) he used to have a crush on her and travelled with her for 3 years. At one point, my boyfriend and I broke up for a couple of months and this created a lot of drama among his friends that created a lot of stress for him. He decided he wanted us to get back together. A lot his “friends” decided they didn’t want to be friends with him anymore if we were dating, these people were once my friends too. Anyway, among all this Dee decided to confront my boyfriend and told him she liked him all along and had always had feelings for him and told him he shouldn’t date me because I was “crazy”, etc. This didn’t sway him at all. He still chose me over her and told me what happened. I confronted Dee about it and told her that she and my boyfriend couldn’t travel like they used to, because if she still liked him and wanted to pretend I didn’t exist (I tried following her on insta and she restricted me and didn’t follow me back, also she’s never liked any of my boyfriend’s posts about me) then obviously it would be inappropriate for them to stay overnight alone together. I told her that the things she said about me weren’t true and she can’t just slap labels on me like that, I just wanted to clear the air. My boyfriend agreed to this and had no problem with traveling with her among friends or if I went along. This upset her so much she told my boyfriend she wanted nothing to do with him since his girlfriend “was trying to isolate him from his friends.”

This really upset him, and at first he lashed out at me, but I told him to look at the situation and realize how ridiculous it was to be mad at me when she was the one who started the drama, not me. I told him if that’s how it was going to be and he was always going to side with Dee even when she was in the wrong, then I couldn’t take it anymore. He apologized to me and told me he would listen to me from now on and talk things through instead of assuming that I’m trying to control him or that I don’t like his friends, which isn’t at all the case, I was really happy to hear that.

I’m very confused, in my opinion, our relationship is none of any of his friend’s business, especially a female friend he had a history with. I hate drama. But at the same time I can’t ignore something like that, it has to be addressed or else it will continue or get worse. I don’t understand why she waited until my boyfriend was in a serious relationship to tell him that she liked him. I don’t get why she’d drop him after being called out for talking shit and crossing the line. None of this really makes sense to me. I would like for everyone to just get along, I would like for Dee to move on from any feelings she has for my boyfriend and get over them and for them to really just be friends and for no more drama to happen.