sleepovers???

Jillian
Ok so my bf and I have been dating since July 4, I'm 17 he'll be 19 in February, I love him to death and could see myself being with him for a long time and potentially marrying him in the future. my parents really like him and think he is a good guy his mom really likes me so everything is going really well except for one thing. I want to either be able to sleep over at his house or him sleep over at mine I've asked my parents if I could at his and it was a firm no, I don't understand why they think they're condoning sex if they let me stay the night when they know I've been having sex with him for months already I was open with my mom about it and they treat me like an adult in regards to me having sex at 17 so I guess until I'm 18 I can't sleep at his house but what about him sleeping at mine is there the same stigma around it? Is it disrespectful to my parents if he does? I'm just trying o understand the parents logic behind not letting sleepovers happen. Sorry this was so long but if anyone has advice or their opinion on it I would like to know thank you