I occasionally use Shadowmere when traveling. Problem is when I don't want to take Shadowmere...too bad, here he (she?) comes.

Shadowmere frequently gets in they way during melee combat or takes my kills. Anybody got a solution for Shadowmere showing up everywhere?

If you have Dawnguard, summon Arvak and ride him first. Riding any horse will set the previous horse's location. Otherwise, Shadowmere will follow when you fast travel.