Is it ok to email now n again or does it look like im pursuing?

My male friend in work is crap at contact the only time hes emailed me first was to moan i hung up on him when i was phoning someone else,when he was gonna lend me something and forgot and when he thought hed offended me. I only email him every two weeks or so with hows u as we work in different departments and i barely see him in the corridor. He is quite worksworthy so he takes his job serious so dont know if thats why. He replies to my mails ie we were emailing back n forth on friday all day and yet he wont email me first.