From Longman Dictionary of Contemporary Englishsplit up phrasal verb1 SSFRELATIONSHIPDIVORCEif people split up, or if someone splits them up, they end a marriage or relationship with each other Steve’s parents split up when he was four. with I thought she’d split up with her boyfriend.split somebody ↔ up Why would she try to split us up?2 SEPARATEto divide people into different groups, or to be divided into groups Please don’t split up when we get to the museum.split something/somebody ↔ up The teacher split up the class into three groups.3 split something ↔ up to divide something into different partssplit something ↔ up into The house has now been split up into individual flats.Split up is a reciprocal verb. This type of verb is used when saying that two or more people or things do something that involves both or all of them: Her mum and dad split up. You can also say: Her mum split up with her dad.Her mum and dad split up with each other. → split→ See Verb table
Examples from the Corpussplit up• They're always arguing but I don't think they'll ever split up.• We'd have a much better chance of finding the child if we split up into groups.• The U.N. team split up to inspect several sites in the south of the country.• Have you heard? Katie's splitting up with Andrew!• He started drinking heavily after he split up with Debbie.split with• This was after David had split up with Hermione and was nursing a broken heart.• His father died, he lost his job and he split up with his girlfriend, Darlington magistrates heard.• Taylor's splitting up with his wife.• However, I've recently split up with my boyfriend because of the pressures of failing to conceive.split into• Now just expand those three sentences into a synopsis and split it up into chapters.• Heals and Moods split us up into four groups.From Longman Business Dictionarysplit-upˈsplit-up noun [countable]COMMERCE an occasion when an organization is divided into two or more partsSplit-ups remain difficult in many cases because of company law obstacles.