if you wanted to do something like study for a degree or travel round Mongolia for a few months, it might be helpful to do it alone, especially if your partner isn't into that sort of thing. A cousin of mine regularly spends a month or two every year travelling, either alone or with (female) friends or relatives, which she loves doing, while her husband stays home doing carpentry, which he loves doing.
Neither of them calls it a sabbatical, but the name fits all the same.