As an aquarius that has dated pisces before, I can only give you my perspective.

Going out and socializing with a pisces has always been great fun and very exciting. They tend to have a lot more energy and seem to be a great balance for the somewhat calm and laid back aquarius, giving him/her little spurts of energy and drawing him/her out of the shell.
While aquarius tend to go through phases where they love to talk and socialize, they do eventually need some quiet time to "digest" what's going on in their environment.
Pisces don't have much need for a break from socializing being the energetic, people oriented creatures that they are.
So the challenge lies in the fact that an aquarius needs to receed into the shell after a period of socializing whereas a pisces doesn't much care to have time off from interacting whith you and might take the distance personally.
Coincidentally, the best way to loose an aquarius is to not give him/her enough personal space and time "off", which makes an aquarius feel overwhelmed.

The best way to approach the issue is probably to leave it up to the aquarius to decide when to meet,talk, socialize whenever he/she seems to be getting more distant, and live out your social urges by going out with friends and family.
That way you both get what you need without putting to much pressure on the other person.