Spearmint really does need to be in a pot. I used to grow it and stuff goes crazy if not kept up with. Once it takes root in the ground, it can end up being a ground cover completely by accident and very hard to kill at that point. I also don't recommend a pot with a bottom that has one of those self-watering deals where you pour water and it gets soaked up by the roots with this plant either. My spearmint tried to grow new shoots out through it. lol.
The sage and lemonbalm can get a good size so like already said, should be considered for planting in the ground. If you can't do this and a pot is all you can do, plant them in separate pots and trim them up from time to time so they don't go over board. If you end up with too much sage, harvest some and make some sage bundles! Also always repot them when they need it and use new soil for the nutrients they need.