parents and sleep overs with boyfriend

Hey I just wanted some advice on this topic. I (21F) have recently moved home from college for the foreseeable future (graduating this month) and I have a boyfriend (21M) of 1 year and a couple months who I met there at uni. He lives a long enough distance away from me where meeting up just for a couple hours in a day would be slightly more inconvenient than if I were to stay over at his and we could hang out for a bit. This is where the problem lies.
Relationship conversations have been sort of taboo in my household, not that we (my sister and I) were strictly forbidden, but it would just greatly disappoint my parents if I had any relationships before having a stable job. Unfortunately (for them) I have met someone absolutely amazing and I’ve found myself to be quite deeply in love. I told my parents last year and my dad seemed to take it quite well but my mum on the other hand did not. It might’ve come from a place of fear but she told me I was a disappointment and a disgrace and was quite cold to me for months. It seems like she has gotten over this now and even my sister who is 2 years younger than me has her own boyfriend who she was fine about.
I thought she had gotten completely over this but I spoke to my dad and it turns out she still believes that I’m not serious about this relationship and I’m just doing it for fun (by which she means sex) and all that fun stuff. So clearly there is still some sort of (for lack of a better word) resentment there.
I want to talk about staying over at his when we hang out because it would be easier. I am worried my parents will say no and also have no idea how to start or go about this conversation considering how she reacted when I first told her I have a boyfriend.
Sorry this is so long and I’m just rambling but any advice would be appreciated. :)