You should only have to remove the outer tie rod end to get the boot on. Do you mean the small end? Make sure to have it re aligned after taking apart the tie rod end.

If you are taking about the big end it should fit easy. The boots are not designed to keep fluid in just to keep dust out of the inner tie rod end. So thy don't have to fit tight just snug you may have the wrong boot. If I remember rite thy are make out of a hard plastic so thy probably will not stretch.