Is he messing with her?

My bf had been messaging this one girl off n on on for the past month. I didn’t say anything about it till now when he deleted her thread . He claim she just a friend that he met at work and he hasn’t been to her house . But why was the thread deleted? So I message her . Didn’t come off wrong

I’m like hey this is ____gf sorry to interrupt I was just wondering if you and my bf hang out outside of work or if there’s anything going on between y’all ...and know what she says ? SHE GOES OFF

telling me she doesn’t answer to nobody and telling me to ask him and I’m like I did ask him now I’m asking you . Then she calls me all out my name n I’m like there’s no need for name calling I didn’t come at you sideways it’s a yes or no question really are y’all seeing each other outside of work . And she reply’s get off my phone bitch . And I’m like damn dick that good huh and she’s like idk bout the dick but his head game nice and he can go for a long time . I know she was making that up . I laughed and said send me the proof

I tell my bf I messaged her before I even messaged her and he was fine with it . He’s like there nothing going on between us u goin feel stupid when she reply . Then when I told him what she said and how she acted he was calling me a little girl for messaging her . Then he broke up with me cuz I can’t trust him .

Why would she get mad if there was nothing going on between them? If she was just a friend