A few thoughts,
I get the impression that early on, ML was truly in love with the female lead. That is why he approached her and told her out of the gate that he could take care of her, if need be. He even married her, when he found out she was an heir. But then he entered the Addams family and realized that things were not as they seem. While she wasn't the nicest, her family is insufferable to me. They look down on the ML, but yet, need him all at the same time.
This introduction of the friend/ex has been intriguing. He is clearly there to mess things up. I wouldn't be surprised if he was in cahoots with the matchmaker lady. However, he is clearly a sociopath. Attempting to kill a dog that you can't have is next level psychotic. And when that older couple mused, he reminded them of the troubled little boy they took in and fed, who'd killed a dog back then, I knew we were dealing with a real evil villain. I get that the ML is jealous of him, but he also needs to be cautious. He has seen enough to know that this guy is dangerous.
I was so annoyed with the ML's siblings when they showed up to talk her out of the divorce. Not only did that reek of selfish greed on their part, but it's literally none of their business. While her family is no cake walk, the ML's family has some holes too. His family forcing him to stay miserable so that they will be financially taken care of, is wack.
I get the feeling that something happened to the female lead that we haven't been privy to yet. I don't think this is just stress from loss of a brother. And I feel like it may be tied to the psychopath. It has gotten enjoyable watching them fall in love all over again. I will keep watching.