Here’s my opinion:
Based on the information you provided, the guy you’re dating probably lacks a bit of maturity. That’s more than likely due to his age. For him, texting is more a[b] game [/b]than anything else. He’s just having fun. Now, if he had a bit more maturity, he’d realize that it’s not very considerate towards you to show that much attention to women that aren’t even his friends. But in his mind, I’m sure it’s just a game. However, I hope you realize that immature guys often look for the “hottest” women. Deep down, they’re the ones they want to go out with. That’s more than likely another subconscious (or not) reason why he’s texting them, even though he won’t admit it. But that’s normal (or I’d say natural… it’s called the male instinct). Should you be concerned? At this point, I’d say maybe a bit, but not too much. He’s just a grown up kid right now. If the guy was 35 yrs old, had a great job, a house, and well settled in life, and on top of that enjoyed texting the “hottest” co-workers in the office, and was in a relationship…. then I’d be concerned. But right now, it’s probably just a phase in his life. If, texting aside, he treats you well and shows you the proper affection on a regular basis, then you shouldn’t feel insecure.