I am overreacting ?

My fiancé has this friend, let's her B. Him and B have been friends for a long time. Which I was fine with, and still am even though one time when my fiancé said they tried hooking up but it didnt work because she turned into a lesbian... I never met B until my birthday this year. She's pretty cool and pretty. So my birthday I saw message between my fainces and B where my fiancé thanked her for coming and whatnot and that he loved her so much. I mean who doenst love close friends? I was still okay. I then started seeing more messages where she started her first text by saying "hey love" "hey hun" and I never had seen these kind of messages before we met . Mind you, I had seen messages between before meeting as well and they're messages were always like "hey, how are you" or "hey how you been, I miss you!!"

But of all a sudden they see each other on my birthday and now they're messages suddenly start with "hey hun, hey love"

Today we started talking about B. She does waxing and I want to wax before heading to Vegas this upcoming weekend. I was holding my fiancés phone at the time and he told me to text her. So I go in his phone and I see messages between them.

It's started with her texting:

Hey, don't mean to bother but I'm still looking for a place"

She's trying to find a place to rent and my fiancé always had someone who knows someone.

My fiancés response was:

" Hey bugaboo 😉 you never bug me, I know a place but it's far"

Before I started to rant about his response let me make something clear. He calls me and the kids bugaboo. It's like a cheesy word to call us, when he's trying to be sweet. So why is he calling this woman bugaboo? Second, why is there a winky face? And third, she never bugs him? Doenst it sound somewhat flirtatious? At least to em it does. And I know some of you will say she's a lesbian and there's noting to worry about. But let's not forget, THEY TRIED HOOKING UP ONCE BUT DIDNT WORK.

So, am I overreacting? Am I being dumb? When I asked him he said he called her Bugaboo because it means someone else. Nothing flirty. Supposedly it's for people who BUG. Stupid I know. And he wanted to make me believe that I was wrong and that he never calls us bugaboo.