Thank you for helping me understand the story.
After checking again, I didn't find sentences describing his cousin and the dude didn't kiss.
I'm just think she's forced and doesn't have romance relationship according to his father's information and her strong reaction to the marriage as below.
About the sister, though I guess she will eventually forgive MC, she still breaks my heart when I'm happy to see that MC started to get out of his room after his father's death for a long time.
If we're able to choose not to take pregnant women or worse daughter(no matter it is true or not, at least she looks like to MC now) or any other women that we don't like as lovers, which they will become no more than a NPC in the game, I guess that will be ok for me.(?)
I personally think the one which is not in love with me and will not take my girls away(important) is just a stranger.
BTW,
Supportive family members are so sweet.
Two people are still a harem, right? haha