I think you've got the gist of the meaning. A less clunky way to word it in English (depending on context, of course!) might be "I don't want you (him) to go!", depending on who is a part of the conversation and the context of their relationship.
Grammatically-speaking, I think you've got the idea as well. The -のは turns it into the topic of the sentence, if I remember my terminology correctly. It's been a long time since I've looked at a grammar textbook for any language...
Another simplified example:
充電する (to charge [say, a cell phone])
充電できる (to be able to charge)
充電できない (to be unable to charge)
充電できなくなる (to become unable to charge)
携帯を充電できなくなるのはイヤだ！→ I don't wanna not be able to charge my phone!
I suppose it's a fairly subtle difference when you look at a literal English translation of the grammar, but it's more about what makes a grammatically correct sentence in Japanese than conveying specific intricacies, at least from a layman's (read: my) point of view.
Also something to be noted is that native speakers will commonly leave off the "は" in instances such as this.
HTH and best of luck!