Not only did my wife and his family travel without telling me, but he didn't contact me for so many days. Why would he do that?

I'm sorry to hear about your trouble. There are many possibilities for this situation, and the following are some reasons that may lead him to do so:

1. He may have forgotten your existence or been busy planning a trip, forgetting that you need to tell you before the trip.

He may have realized that he didn't tell you before the trip, but he chose not to contact you because he might think you would object or didn't want you to know.

He may have decided to end his relationship with you, but he didn't know how to tell you, so he chose not to contact you.

In either case, if you feel uncomfortable and confused, you should choose to communicate with him. You can contact him by phone or text message to express your worries and confusion. If he can explain clearly and make people feel comfortable, then your relationship can continue. If he can't explain or is indifferent to your feelings, then you may need to reconsider whether the your relationship is worth continuing.