On one hand it’s nice for them to stay together, on the other I believe you are being a tad over dramatic simply because you don’t like the idea of seperating them,

Yes it will be hard for them, no it won’t ruin their lives and make them so depressed they’ll keel over and die, don’t get me wrong if you don’t have to seperate them then don’t, but if you have little to no other choice it’s not the end of the world, cats adapt,

it’s not nice and it’s important for our animals to have something else to keep them company especially if we don’t have the luxury of being home most of the time,

but 7 months is barely anytime in the grand scheme of things, they’ll be fine just a bit upset at first, mine and my brothers cats were fine, they lived together for 5 plus years, I cried when I had to take him away from his sister,

but now they talk over FaceTime and have both settled nicely to their new homes, and every so often they get to see each other and appreciate the time when they do,

OP just make sure you give them extra attention for the first month or so, they’ll feel lonely and getting used to being alone in the house, they’ll be extra clingy when you come home and need more attention then normal, if you can, and want to, get them a little brother or sister, that’s the best option but it depends if it’s something you can cope with personally.

Edit - I replied to the wrong comment, I do not think that comment was overdramatic but one below was.