Your soil looks way to wet for that plant. cut away anything mushy, then repot the plant in better draining soil. Only water as the top couple inches feel dry and never let the roots stay wet. Make sure the container has good drainage. You can dip the root end in a fungicde or dust it with cinnamon before planting..
I agree, things look too wet. Overwatering is probably the #1 way that people kill their plants, so I suspect your black thumb is probably just a heavy hand with the watering can. Succulents need even less water than regular plants so it's that much more important not to overwater them.
you will want to get some sandy soil in there that allows for good drainage. make sure the potter that you have has plenty of holes in the bottom as well. you can even add a few small rocks to the bottom of the pot before putting your new soil in. (hopefully everyone else agrees and i am not providing crappy info) :)
I am fortunate here...we live on a rise between Bayou Manchac and Muddy creek...the area around us may flood and we become an island, but the subdivision stays high and dry.And yes, palmettos are in walking distance...grin
Yes, plants need to breathe and being able to do it through the sides of an unglazed pot is pretty handy when the soil is too wet all around. Roots need air and if you don't give it to them one way or another they will suffer.
mscala- you need to either get 1) a bag of cactus mix or 2) a bag of perlite and some chick grit. There are other things that could be added but those are the two most available and vital. You have to mix up some new soil that is at least half perlite and chick grit if not more. Ideally you would use fresh potting mix as well.
Then cut cleanly through healthy tissue with a sharp knife, let it air a tad, dip it in one of the recommended powders from above, put it in the moistened well draining mix that you made and put it in bright indirect light.
Then get out of its way- don't water it. For how long I can't tell you because the temperature, wind, and humidity influence it a great deal and I don't even know if it is being kept indoors or out.
We can get to that later.
For now get that new mix together!