After my boyfriend came back from meeting his family, he changed, ignored me, and became cold to me?

It means that you feel a little disappointed because you did not behave well in his home. Communicate with him and tell him that you are a little nervous and restrained in his home. You also realize it and you will gradually change it in the future. I was like this when I went to my girlfriend's house, and then I was indifferent for a few days, and then everything was fine after a few days

It's natural to do things, but we also have to talk and communicate together. To put it harshly, just look at it. Nannies can also do things. Don’t forget to keep it in your heart. It’s just a metaphor. Since you want to be a family member, you should think like this. Slowly adjust your mind and treat their family members as your own.

As for how to explain it, of course just keep it in your heart. Tell the truth, just say that you were just a little restrained at first and thought his family is still very good, and you will slowly adjust.