I really know nothing of Peace lillies, but I keep replying because I have one; I normally wouldn't buy one, but the vast majority of my exotic plants I have received as gifts -- women just like giving me plants
.
This plant was also given to me and since I don't do container gardening, nor do I like having house plants; I did a little research and found that it hates direct sun, so I planted it under my live oak tree.
However, I've also heard that it doesn't like a lot of watering, and many owners wait for the leaves to droop before watering, so maybe you should think about doing that.
Personally, I very infrequently water the plant, much less frequent than once per week. I only do it when we haven't had rain in a very long time, which is what we're going thru now with a minor drought and my plant does fine, but then again it's in the ground.
However, another thought came to mind that may be a problem with your plant. You live in the UAE, I'm not sure, but I would think that your area has very low humidity...correct?
If so, you may want to occasionally mist your plant. I understand that they like
at least 40% humidity. You might even want to mist the top layer of the soil enough to where it's moist, but not enough to where it soaks into the soil, that way it evaporates and creates a little humidity. I think it's worth a try.
So to recap, I would recommend waiting for the leaves to droop before watering and to some way increase humidity level -- it's a tropical plant and it's humid in the tropics.
BTW, here a few pics on my Peace Lily, I thought I'd add since it just started flowering. I took a couple pics of at least three very rough-looking leaves. I think the problem is that it receives too much direct sunlight (morning sun), so I'm thinking of planting something in front of it as the sun rises, otherwise the live oak provides very good shade.