I think my odor problem first started after being penetrated anally as well. I think that you should consider a colonic FROM A PROFESSIONAL and the use of some pro biotic beads and some anal kegels.
I know this sucks but i think that you should evade the anal sex for a while until you nip this in the bud (no pun intended) because if you are having relations with someone else who has the same problem I think that it could become worse.
Just look into my suggestions, at worst you spend seven dollars for some pro biotic beads at the pharmacy. Hope this is of some help.
But also see a proctologist or your general doctor. They may be able to prescribe some nystatin or other antibacterial for the fungus issue.