Am I overreacting?

Alayna
My boyfriend of almost a year and a half has an ex girlfriend who is his family's insurance agent AND his brother is marrying her sister also. It's just a mess, well my boyfriend is Mexican and his parents don't speak very good English so she goes to him or he goes to her for any questions about insurance whatever. I never really cared about it because he always told me it was only business. Well the beginning of the year her dad and sister had both passed away, which is terrible and I felt bad, he went to the funerals to show his condolences to not only her but his future sister in law, but I saw messages of her being upset about the passing me (they both passed in January and February) and they talked about more than just insurance. I don't understand why she feels the need to come to my boyfriend for comfort when she has a fiancé who she had cheated on my boyfriend with which is why they broke up? I understand it's hard to lose a family member but I wouldn't go to my ex boyfriend, I would go to my current SO or friends. I just feel hurt because he swore for months that it was just business and I found out otherwise. Am I wrong for feeling hurt? I just don't think it's necessary. And I also asked him to tell her to speak to his sisters about insurance for their parents instead of him but he said no because I'm being psycho. Am I? 
Also I would like to add she was upset about her friends blah blah blah or was just having a bad day so that's when she would text him. I just think it's innapropriate.