Well, as of about mid April most of the breeding activity in pythons and boas comes to a halt in most states. In other words the breeding season for most species, is basically over until October or November. Of course, perhaps some of the Northern states may have later spring seasons and the breeding may go on there for a month or two more. What state are you in?
Also, if the "problem" was the 12 foot female then you would see him mounting her and breeding her repeatedly every day or two for a couple of months. If you don't witness this obvious breeding activity then the cause may simply be due to stress if they are housed together. Though I rarely see burmese stress to a level that causes them to go off food.
-----
David Beauchemin
High End Herps.Inc
http://HighEndHerps.com