My(24F) boyfriend's (23M) friend/old fling(20F) is going to visit and I am not sure how to react.

My (24F) boyfriend(23) and I have been friends for over 5 years, together unofficially for 2, and dating officially for 1.5. He's everything I could hope for in a man, and there is honestly nothing wrong in our relationship. This is just based on the the idea that I am not sure how I will react, or how I should act, when I meet the girl he used to be interested in.

Okay, so since my boyfriend and I have been friends for years before we got together, we knew a lot about each other, including our romantic lives. He knew basically everything about mine and I knew about his. So I knew this girl (20), let's call her Lucy, is someone he had a thing for, and a thing with, in the past. When we were just friends, I was there when he texted her, snapchatted her, and even skyped her. I thought that they would be cute together, until I realized she lived on the other side of the states. I was cool with this girl and the relationship she had with him, because he was just a friend and I wasn't looking at him romantically at the time.

Well flash forward to when my boyfriend and I start seeing each other on a nonexclusive level, I noticed that Lucy and him still chat, but not too often. She will hit him up once every few months about something random, then saying "I miss you" and whatnot. We were nonexclusive so I didn't really care. We were free to see other people, pretty open about everything still and so he showed me everything and I would even comment how to respond sometimes to help his game. (So weird now! Lol!) At this point I had no feelings of jealousy or anything.

When we go forward a few more months, we become very serious, and decide to become official couple now. Lucy is one of the first people to congratulate him/us via Snapchat. I liked that because he sent her the snap of us being together, and she responded, acknowledging that we are a couple.

Well our relationship goes on and we are about at the one year mark, when I notice Lucy is still hitting him up from time to time. Not really bothersome to me because she's a friend of his, she acknowledged we are together, and I trust him. Well since my boyfriend and I are very open with each other, we look at each other's snaps together. And a couple times we would open Lucy's snaps and she would send a flattering selfie that increasingly seemed to get flirtier and flirtier. I even made a comment at one point saying "she is starting to get kind of flirty". (I don't remember what his response to that was).

And sometimes she would move the snaps to messages, and he would show me those messages most of the time, but not always. The thing that kind of bothered me was that sometimes when a friend texts him he won't respond right away, but with her he seemed to be focused on responding right away. At that point my jealousy was starting to peak out a little, because he would text her while I was trying to tell him something.

There was one point where I was starting to get a sick feeling inside of me, that he wasn't telling or showing me the whole story about Lucy. It's hard to explain but it's not that I thought HE was saying things TO HER that would upset me or anything, or was doing anything that was considered cheating, but I had a feeling he was starting to not show me his messages with her because he didn't want me to get upset about the way SHE has been communicating WITH HIM. But again, it was just a hunch at that point.

Well one night he fell asleep and I was still awake. Something was really eating up inside of me that was telling me I should look more into Lucy. I knew it wasn't right and I should have just talked to my boyfriend, but instead I looked at his phone and opened his Snapchat history with Lucy. And I can't recall all the texts but what I remember most was the selfie she sent him (the kind that doesn't disappear in 10 seconds) with hearts around her face saying "wish you were here" and whatnot. (Saved by her). I couldn't look at anymore and I went to sleep, shaken up. I felt so disrespected as a person, and felt like she was disrespecting my relationship with him. It also made me think that she is either 1) a bitch who doesn't care about our feelings or relationship, or 2) she is very dumb and truly doesn't think there was anything wrong with what she sent. Either way, I cried myself quietly to sleep that night.

The next morning we go to church together and he knows something is up. When we get home we talk and I tell him that I had a bad feeling about Lucy. I told him I looked at his phone because I was suspicious about Lucy. I told him that I was sorry, and that it wasn't because I didn't trust him, but it was because I didn't trust Lucy and how she sends him stuff. I felt like he was being put in a position that was kind of hard to bring up to me.

Then I told him how I saw the snapchat of her with the hearts and how I felt disrespected as a person by her, because she knew I was his girlfriend, and how she knew he is in a relationship.

He was never mad, he sincerely understood my standpoint and told me that he knows he was in the wrong when he didn't tell Lucy to stop with the flirty stuff. He just didn't know how to approach it because even though they had some feelings in the past, they knew nothing would come of it because of distance, so they decided to stay just friends, and some of the stuff she sends is just the way she is. He also reassured me how much he loved ME and how he sees a serious future together with me. He promised he would tell her to stop with the flirty stuff the next time it happened.

She still hits him up from time to time but hasn't done the flirty stuff since (he shows me whenever she does hit him up), so he hasn't had a chance to say it. I'm not asking him to bring it up out of nowhere either.

Now, he recently told me that Lucy reached out to him and told him that she is going to be visiting the area over summer. She wants to catch up with him and whatnot, and my boyfriend is inviting me to go. I told him that I still don't like her because of the past, and he totally understands. He told me that maybe it's a good way for her to see me, and good to show her in person how in love we are. I definitely respect his standpoint, and I understand it, and I agree with him. The thing is I don't know how I will react or how I should react when I see her.

On one hand, I don't want to meet her, but I don't want my boyfriend to meet her by himself. So in a sense, I don't want me or my boyfriend to meet her when she comes. But I feel like that's selfish, and also won't fix anything. So that is not really an option for me.

So on the other hand, I meet her. But when I do, am I nice? Do I try to get along with her? Or do I just straight up cold shoulder, resting bitch face her? I honestly can't be sure what my first nature reaction would be, or how I SHOULD react in the first place.

What do you guys think? How would you react to meeting a girl who was sending flirty things to your man?

I feel like i should put on a smile and shake her hand, but at the same time I feel like that's very fake of me because I actually want to knock her teeth out and smash her face in...

TL;DR Boyfriend is friends with a girl who is his former romantic interest, but this girl sends him flirty things when she knows he is in a relationship. Now she is visiting the area and wants to meet up with my boyfriend. Boyfriend is inviting me to meet her so show her how in love we are. How should I react when I meet the girl who intentionally or unintentionally flirted with my boyfriend?