What does it mean when a guy shows his vulnerable side?

Fitbeauty
I'm a manager at a gym and this member has been flirting with me for the past 2 months, at first it was subtle but it's gotten progressively intense. He stares at me A LOT, seeks me out, offers to help me out whenever I need it, brings me food sometimes, teases me and shows off for me. His newest thing is winking at me and one time called me "sweatheart" and another "darlin" (and he does NOT use those words with anyone else and didn't with me at first) Everytime I show interest in him (ie flirt back, touch his arm, laugh ect) that just makes him flirt even harder. Sometimes he acts weird like he's nervous or something, other times he's overly funny like he's trying hard. He's lately been staying late to talk to me usually its about our interests, traveling or silly stuff. We found we think alike & have a lot in common. He always initiates. Lately he's been talking about how he's sick of dating women who are fake and mean. He wants a nice girl and then the other day, he came up to me and started talking about his family and what led him down the path of working out so much, turns out someone said something to him and it caused a major insecurity in him. We talked about other stuff too but he was just so open and honest about it. Why does he feel like he can tell me these things?
What does it mean when a guy shows his vulnerable side?
5 Opinion