jealous?

So I just want to hear other people's thoughts on this. Tell me if I'm wrong and being a jealous girlfriend. So my boyfriend is a manger at a medical imaging company, so of course he has to over look everyone and keep in contact, but he is always texting this girl who is the manager of another office close by. He gets texts late at night and when ever someone calls him from work it's always her. He talks on the phone with her when I'm around so it's not like he's being sneaky it just bugs me. I looked this girl up on Facebook to she's young single and pretty. Yeah I facebooked stalked her. I have mentioned a few times that it bugs me that he's always on the phone with her or texting her but it continues. Should I drop it, am I being ridiculous?