I haven't had time to listen to these podcasts yet, but I did read your blog here
http://www.achillesgene.com/blog/alexan ... ommenting=about Alexander and Hephaestion's relationship.
For me, Hephaestion not being interested in a physical relationship with Alexander beyond adolescence just doesn't work. It sounds too romantic - Alexander heaped more and more authority on him out of unrequited love? Plus, Hephaestion would have been a bit dumb to turn down a king if he was interested in him as normally it would have meant a path to power and favouritism, and if he'd turned him down, who knows what Alexander's revenge might have been?
A more plausible scenario would seem to be that the physical side of the relationship petered out. For one, Alexander was interested in boys not men. That might have been dictated by social convention, but as Hephaestion became less appealing as he grew older, boys such as Bagoas probably took his place.
Secondly, there may have been social pressure to end the relationship. Alexander refused to marry before he set out for Asia. This might have been partly because he was in a close relationship with Hephaestion. There are lots of other reason too, such as not wanting to leave a potential heir at home who could be used to displace him. He had killed off all his viable male relatives, and it would leave too much power and temptation in the hands of others.
There may have been increasing peer pressure for Alexander and Hephaestion to end the relationship after Issus. Parmenion chose Barsine (principally because she spoke Greek and was a widow) as Alexander's 'prize' from the captured harem at Damascus. This was allegedly the first woman he slept with, and it may have been Parmenion's not-so subtle way of saying, it's time to move on or you will lose the respect of the army.
Thirdly, they would have begun to feel social pressure not to appear weak and feminine. It would have been difficult for either of them to exert authority if they had been seen in the eyes of the majority of the army as someone's 'boy', particularly for Hephaestion. If he was to have any respect as an independent commander, they would have had to end the relationship. Interestingly, shortly after Issus, we learn of Hephaestion's first independent missions - appointing the king of Sidon, commanding the supply fleet on the march into Egypt, liaising with Athens, and bridge building over the Euphrates. Pay off for ending the relationship?
If they did continue the physical side of the relationship, if would have become sporadic as Hephaestion was often absent for months. It would also have had to have been very covert for it not to have been gossiped about, particularly after Alexander's marriage to Roxane.
If though they did end the physical side of the relationship before it became something out of the ordinary, in later years Alexander would have legitimately been able to compare his friendship with Craterus with that of his friendship for Hephaestion without, perhaps, too much fear of sniggering.
That doesn't mean though that the love ceased (bit wary of using that word but affection isn't strong enough to explain Alexander's reaction to Hephaestion's death). Alexander and Hephaestion had probably known each other since childhood. The traditional view is that they met when Aristotle took over Alexander's education and the group of Pages to accompany him was chosen. Hephaestion though was from the neighbourhood of Pella, if not the city itself, and they may well have known each other since childhood. Alexander certainly had companions of his own age as, when he was about 10, he and another boy debated before the Athenian ambassadors. If the other boy was a son of Philip's it would have been worth a mention, and Alexander would certainly have needed other boys of his own age to compete against in his physical education as well as his intellectual education.
In this respect, Hephaestion functioned not only as Alexander's friend, but probably as a brother too. Given the trouble Philip had with his own rebellious half-brothers, Alexander would have been very wary of trusting any of his half-brothers. They were his rivals and any relationships between them were probably fiercely competitive. With the lack of any full brother (that we know of) that he could trust, Alexander may have been isolated within the family. Hephaestion, with no major power-based family interest to motivate him, only had his own interests at heart in befriending Alexander. Alexander could trust him because he depended upon Alexander for advancement. If they grew up together sharing an idolisation of heroes such as Achilles, much like boys today with sporting heroes and their visit to Troy suggests they did, they would have formed a strong emotional bond which would have outlasted any physical attraction.