To be honest, I can see why you would be annoyed! Especially when its a LDR, I think its really important to make time to talk. You don't sound clingy at all, and I understand what you're saying- you just want him to choose to talk to you sometimes, not always, but if talking to you means he spends half an hour less exercising then I don't think you're being unreasonable asking him to do so.
How have you tried bringing the subject up? Obviously if you go in all guns blazing (not that I'm saying you do) he'll get defensive. Just explain you're finding it hard enough having a LDR and you appreciate you'll be together come September but until then you'd appreciate him making more of an effort to talk to you. Discuss it calmly and hopfully he'll start to see where you're coming from!