have a thing going

have a thing going (with someone)

To have or be in the midst of a romantic or sexual relationship with someone. I hear you have a thing going with Jeff from accounting. Is that true? I have a thing going with a lady across town, but it's nothing too serious.
See also: going, have, thing
Farlex Dictionary of Idioms.

have a thing going (with someone)

 and have something going (with someone)
Fig. to have a romance or a love affair with someone. John and Mary have a thing going. Bill has something going with Ann.
See also: going, have, thing
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • have a thing going (with someone)
  • have something going (with someone)
  • (have) got a thing going (with someone)
  • (have) got something going (with someone)
  • a sugar daddy
  • sugar daddy
  • in (one's) midst
  • in our, their, its, etc. midst
  • midst
  • ship name