Thank you for reaching out to the group regarding your concerns about your ex-partner's new living arrangements. I understand that you have two boys, ages 7 and 10, and that your ex-partner has recently moved in with her new partner, who has a 15-year-old son. You have also mentioned that your two boys now share a bunk bed in the same room due to the crowded living situation.
Regarding your inquiry about your rights as a father, I must emphasize that the rights and responsibilities of parents are generally determined by the Family Court and court orders in your state.
In terms of your ex-partner's obligation to inform you of her new living arrangements, there may or may not be any legal requirements depending on the terms of any existing custody or parenting agreements or court orders. However, it is generally considered a common courtesy for parents to inform each other about significant changes in their children's living arrangements.
If you have concerns about the living situation and its impact on your children, you may want to consider discussing these concerns with your ex-partner in a respectful and constructive manner. If you are unable to reach a mutually agreeable resolution, you may need to seek legal recourse through the appropriate channels.
I hope this information is helpful to you, and I wish you the best of luck in resolving your concerns. I do have one question, do you have room to house your young sons and would they be amendble to come and live with you on a more permanent basis?