The MC is EXTREMELY possessive at the start. Not the normal level. He has his reasons and insecurities and it improves over time. So, no need to be discouraged due to the first part of the novel as the amount of possessively cannot be tolerated by normal people. He is obsessed with the only person who stayed with him and ML is okay with as his obsession gives the insecure him security. Going through the story, they recognize the problems in their relationship and changes it. But, for people who don’t like yandere, it is better to steer clear because even though he improves and talks to him sweetly, shares the housework and let ML have... more>> friends, he still doesn’t like ML knowing too much people. 

PS:- You cannot misunderstand the bodyguards and people watching ML as not trusting him because he has enemies and has been kidnapped once. It’s better to be safe than sorry along with a bit of surety. <<less