I agree. I personally like Ridhima's character. Although she may come across as greedy and she does pretend to care for social causes(when she actually cares more for just media attention), in my opinion that makes her more human ( I've seen a few people like that in my life). Also to me she seems like she genuinely cares about Om.
As far as her confronting Om about Bela, I don't think she was completely wrong in doing that. May be the timing and the way she just blurted it out was something that could have been avoided. I mean they were in the middle of a family function, and since they have been together for three years now, she should have understood how important family is to him, and maybe chosen another time. On the other hand, I also think that Om reacted in a way that I personally hadn't expected him to react in(based on his characterization so far). But I guess that reaction made him more relatable and human. He was obviously much more affected by the accusation of his fidelity because of issues with his parents.
And as for the 'lets end this', I think he meant the argument/discussion. I don't really think Om is the kind of person to end a three year relationship in a jiffy, without discussing it. But you never know.