My daughters bf's parents don't like me
My 16 daughter has been dating a 16 yr old nice young man for 6 months now. His parents are divorced but co-parent well. I have been a single mother since my daughter was born-by choice-meaning I am very involved in her life since I play mom and dad role. I also have a business open 7 days a week so my life is crazy. I don't smoke or drink or do drugs. I treat my daughters like a son as he spends a lot of time with us. I have always been kind and beyond generous to him and to his parents and always offer to help with his other little siblings if they want to go out etc (I love kids). I am a cool mom and have always been really good with young kids, teenagers, and adults in general. But for some reason my daughters bf's parents do NOT like me.
He has has admitted they don't and he doesn't understand why and has argued defending me a few times. My daughter goes to a private school and like him, also does not drink, smoke or do drugs. If anything, I should/could have a problem with them-he has terrible grades and doesn't care about school. I try and encourage him. They are Brazilian (been here for many years) and I am half French/half American so our cultures shouldn't be that different. I am hurt, angry, and beginning to feel that maybe my daughter should not spend time at his house knowing they think so bad of me. They pretend and are very very fake with me but my daughter and I feel the tension.
What am I doing wrong? What can I do? Because I'm pretty upset over it.