I'd say stick to your guns. You stated quite clearly that "this sexual anal play on him is a turn-off to me".
With that strong of feelings, I would not back down, if even for his pleasure. This is not something that he MUST have... just a thrill for him.
If you're OK with ocassionally giving him this thrill, well, OK then. But you sound like this is across the line, and so, I differ from the other advice posted here by others.
Don't comprimise against your feelings if you don't want to do it. Instead, find something else that he likes and indulge in that. Make sure he's in the same head space as you are, if that is that sex is an expression of Love, and not Lust or Kink.
Or am I reading too much into your two line question?