Many different languages translates the original Greek word "συζεύγνυμι" (suzeugnumi, phonetic spelling "sood-zyoog'-noo-mee") differently. This brings a specific flavour to the final understanding. For example, closest translation Ukrainian "спарував" to English language would be "coupled" in the meaning of "put them as a couple". English translates as "joined", "zusammengefügt" in German or "сочетал" in Russian, all translations brings a bit different impulses how to understand this. If German translation would understand it as "put together" in the meaning of "to put together two partners for a common interests", then Ukrainian flavour would narrow it down more to "coupled for home". The Russian translation would be even more different, something like "legally affiliated" or "juridically united" and is associated with an official process in the register office. Therefore, when a Russian-speaking person would hear the translation of "συζεύγνυμι", then there would be the imagination of a person wearing mantle and registering an act of civil marital status, asking for the signatures of the engaged. Therefore the expression of "Got joined", Russian speaking will see God as a lawyer, who joins two people with a various kind of obligations, rules and requirements, issuing them a legal document that is supported by the civil law and the Church. However, it is important to consider the culture of the environment, history of the author and context of the language, which was used when Matthew was writing the Gospel. The Greek word "suzeugnumi" (συζεύγνυμι) is actually very close to the German understanding. It actually means in expanded explanation as "better life for a certain goal being together, instead of living for the same thing separately". Exactly that goal, for which marriage is made, can guarantee the strength of partnership. Therefore, if two people are συζεύγνυμι (joined) by a business, then they will live for the business, because they will do it better being together. The guarantee for their partnership will be business. The same way, if God συζεύγνυμι (joins) two people, He joins them for Himself at first place. Such couple will have the goal to serve God as a common interest. Note that his word in the New Testament can be found only two times: Matthew 19:6 and Mark 10:9.
Jesus taught when God συζεύγνυμι (joins) something, then mankind should not separate. By that He is clearly asking not to interfere in what He planned. One or another connected partner should not turn away from Him, should not stop serving Him and must not stop support his spouse maintaining such joint. In this are all plans of the marriage: to serve God. Various plans of the couple are supposed to be aligned the way that the common goal to serve Him remained unchanged through their lives. However, when this goal has been changed and therefore vanished, due to partners have been lost their initial meaning of their marriage and continue living for other purposes, like children or business or estate, then despite of the remaining quality of the marriage they are happy or not, such partnership is no longer συζεύγνυμι (joined) by God. At this point it can be declared that the mankind had indeed separated what God joined together. But is this exactly a time for an actual divorce?
Christ also taught that it is enough to "look at someone with lust" and it is already an adultery deep in the heart. If the Old Testament counted law violation by an actual act of breaking some specific rule, the New Testament is raising up the level of the threshold: it is enough to only wish something deep in the heart, although physically that did not yet happened. Therefore if in The Old Testament divorce can be ascertained only by the physical process of divorce, then in The New Testament in order to separate something what God put together is enough to lose a goal, that was given by God to both. That means that an actual marriage can be broken much earlier that it already reaches certain legal process in court.
As we know why certain physical objects are naturally breaking up — and relationships can be considered as a social meta-object, since they joins together certain people — we also know how certain relationship ends its existence.