First it turned out that Khemi could not marry Hiten since her sister was married to Hiten's father, seems fine enough; then Khemi gets married to another man called Arjan with no connection; and then it turns out that Arjan was also DM's son (wonder how many more sons DM had wandering around the region). And so the same problem occurs; and it was earlier shown that Arjan was a decent sort of person, and then the serial shows him slowly becoming a source of all problems.
So, Dharamraj leaves the decision about Khemi-Arjan to Santu, who finally decides that they need to separate; and while nobody likes the decision, it was becoming clear that DM is appreciating what all she has done for the family. But then Khemi faints and you know that she will be pregnant.
But then Arjan is getting instigated by Moullick, who keeps on urging him against Hiten and against DM, and Arjan finally attacks DM (his own father). In this incident, the details of what actually happened is not clear, but DM became unconscious, Arjan died, and Santu became splattered with blood, claiming that she had killed Arjan because he had attached DM.