rather than

  1. I decided to go to the party rather than watch TV.
  2. I decided to go to the party rather than watching TV.
  3. I decided going to the party rather than watching TV.
    Please correct the above and comment.
    Thanks.

Only #1 is correct.

Canadian45,

  1. The boy went out rather than staying at home.
  2. The boy went out rather than stay at home.
    Please correct the above and comment.
    Thanks.

Beeesneees,
Please answer my above query.
Thanks.

Anglophile,
Please answer my above query.
Thanks.

  1. The boy went out rather than stay at home. (Acceptable)
    This sentence could mean: The boy went out (to play) rather than he would stay (idle) at home.

(The usage of ‘rather than’ indicates the doer’s preference. Since, to me, ‘than stay’ stands for ‘than he would stay’, ‘staying’ is not suitable)

Let me also try to explain it the way I think I can. We need to be consistent in the use of verbs as in ‘The boy likes to go out rather than (he would like to) stay in’, ‘He practises swimming rather than (he would practise) running’ etc.

In that case, perhaps you ought to consider:
The boy went out rather than stayed at home.