Just treat them the same way you would a mate or acquiantance.

Text them when you can/feel like it, be honest with them when you're realistically available and be consistent with it. If you're busy on another date tell them, sorry I'm out with a friend.

At the same time if you're sewing your oats you can't get upset because she went and did the same, I think it's unfair to do so. Girls do it to me all of the time so I don't get fussed unless they make a big fuss over it, at what point I cut contact...