Its a mess :( It has been grown in way too little light, probably overwatered from time to time and not watered enough the rest of the time. The splits are from overwatering, or probably just from watering in a soil that doesn't drain fast enough. You can see dead stems (actually leaves) at the base where the plant has scavenged old leaves to stay alive between its periodic drenchings. Here's what you should do. Throw it away and get one that isn't nearly dead. Seriously! But if you can't bring yourself to do that, it it alive and will eventually grow into something attractive. Pot it in a soil that is more grit than soil. A clay pot is useful in humid climates, the plant should not ever be allowed to sit in wet soil for any length of time. Once you have it set up so that it dries out fast, you can water it fairly frequently without fear. It will appreciate full sun for most of the year, but will not be happy during the hotter parts of summer. Find a cool spot with afternoon shade. It will be dormant in summer and will take up hardly any water. If you bake it in full sun for three months while it is dormant then large parts of it, maybe the whole plant, will die. It will grow vigorously in spring and autumn, possibly right through winter if you have good light. It is not frost hardy. It will flower in spring or autumn or both. It needs very little fertiliser. Here's one that I salvaged, photo taken last week:

I do all my repotting in the summer. I am not an expert . If there is a rule, I have probably broken it . I don't do a lot of misting. Not that that isn't good. I am just lazy and doing life to do anything more than once a week. I do get it out of store bought dirt first thing. Usually it is peat based and will not do for my regimen. I use a gentle hose to squirt the dirt off or a small stick or brush to take it off dry and I let it dry for a couple of days. Then I plant. I am in Texas and even here, I have to break my back moving all these things in winter. BUT I just move them back out when the cold snap is over (rolling tables). I could not imagine growing them in Canada. I probably wouldn't be growing cactus if I lived up north. Hats off to all that do. I grow cactus because they allow me to ignore them in our heat.

Getting turface wasn't all that easy. I had to explore the industrial east part of town to get my hands on a 50lb bag (no option for smaller bag). As for granite grit, I went through about 4-5 garden centres to find them as well. It was well worth it because now I know where to go if I run out. As for you, you might need to explore outer skirts of town at feed stores (granite grit) & landscape stores (turface - john deere, etc) Yeah that's what I thought. I'm going to plant them in gritty mix. 1-1-1. I really hope mine will fare well through winter and look as clean as yours do next year :( Will its scars from slug bites go away eventually?

My Fenestraria rhopalophylla is about the same size of yours but my pot is about 1/4 the size. It's grown in 80%+ grit and watered every 5 days or so. It's been under full sun all summer. Wish mine was a bit more picturesque today, but I was late on watering by 2 days this week plus squirrels have been into my succulents (but not lately). The plant has started to absorb two leaves (yellowish) but is putting out at least 6 pairs of new leaves at the same time: For yours, I would recommend watering much less to prevent splitting. Some people can go without watering these for a month! More light would help a lot too, if you have a better spot for it.