No, I don’t think you are over-reacting. But I do think that you’ve moved too quickly into a live-in situation. Your boyfriend has only been divorced two months. He has work to do to figure out his relationship with his ex, his children and his former in-laws.
It’s not his job to help his ex get rid of a boyfriend. It is his job to celebrate his children’s accomplishments and milestone events. Attending their ceremonies reassures them that he didn’t divorce them. Staying with his former family can be misread by his ex as an indication of willingness to consider getting back together. Staying in a motel gives the clear message that things are different now.
I hope you and your boyfriend can talk this over reasonably and calmly. You can’t control what your boyfriend decides to do. You can decide whether you want to live with him while he works out his various relationships and gets emotionally as well as legally divorced.
I wish you well.