Is this considered abuse ? Or am I delusional

So my fiancé of 3 years has been digging to find out about my abusive ex. I didn’t tell him much about him besides the abuse I endured. My fiancé for the past 4 months have been asking me questions about my ex trying to determine his name and if he fathered 2 of my 3 children . Due to the trauma I encountered I refused to give any additional details about my ex to my fiancé because I’m just NOT COMFORTABLE Talking about him he is dead to me .. smh . However, my fiancé is upset with me because he did a truth finder search on my ex and found him and his family and said I deceived him and he wants to break up . I’m very bothered by his reaction and I want to know if I was wrong in this situation or is he over exaggerating? I just hate feeling like I’m not being understanding of how others may feel but I just don’t feel my ex has anything to do with my fiancé and it’s my past my business