Enhance Cheating Evidence Phone Recording

I have a single phone recording that captured what I believe is my husband with another woman. He claims the suspicious sounds are nothing more than the TV and the AC, and has gone so far as to tell me I’m imagining things... (Budget: $250 - $750 USD, Jobs: Audio Editing, Audio Engineering, Audio Mastering, Audio Processing, Audio Production, Audio Services, Sound Design, Voice Talent)