Ah! That is actually a wonderful question Achal! So yes, it’s true that the universe is expanding and “everything” is moving away from “everything”. It’s like space is a fabric on which everything is laid & that whole fabric is being stretched in all directions, resulting in any two points on the fabric moving away from each other. However, the two galaxies being such close neighbors, have a very strong gravitational attraction between them, which wins over this acceleration and expansion of the universe or this stretching of the fabric & thus they are eventually being pulled towards each other, bound to collide. Hope this helped, thanks!