There are several elements of this situation that highlight a positive response by you and your boyfriend to your daughter’s concern. First, your daughter felt it important and safe enough to speak up to you about it. Secondly, you immediately responded to her request making her feel heard and believed. Third, the changes in her body are normal and her sensitivity to what may have been okay years ago and continued (hugging) is no longer okay. She is learning that it is okay and important to know what feels right and that this can change over time.
Next, your boyfriend responded with an openness and understanding and commitment to hearing your daughter out. In addition, he also requested that there be open communication and request to openly apologize. These are healthy responses from you and he and would seem to be serving your daughter’s sense of empowerment, ability to communicate, and boundary setting. These are life skills she will need. This type of responsiveness by you and your boyfriend sound like they are ideal in creating an environment where they can be safely experimented with.
On the other side of the coin, you’ll have to assess if not ending this with your boyfriend is interpreted by your daughter as you not supporting her. If that is the case, then making the choice to end your relationship makes sense. However, you ending the relationship when all your daughter wanted to do was voice her discomfort in a safe environment might be an overreaction and exactly the opposite of what she’d hoped for. There’s not enough information in your question to know how that might be interpreted, but these are the considerations I’d encourage you to make.
Wishing you patience and peace,
Proof Positive Blog @ PsychCentral