From the few affiliate managers I’ve met, it doesn’t seem they earn all that much. The do get some remuneration based on how well the affiliates they manage do but I think it’s nothing more than a 3rd tier remuneration.
Beeing an affilaite manager is a job – you’re not going to get rich at it but it will pay your bills.
However I am sure you can find some gaming positions at a higher level which woulld pay more.
Have a look at these recruitment agencies which focus on the gaming sector:
http://www.pentasia.com/
http://www.esandagaming.com/
good luck ! V