I am uncapable of expressing affection to my family

Hey everyone, hope you are all great, basically what the tittle says.

I am not capable of express afection for my family, I am 20, I live with my mom and my grandma, we argue a lot, is true, and we do say really offensive things, but since the last years my grandma who is 87 is really really offensive with my mom and I, she is constantly saying to my mom that she has miseducated me for letting me going to parties, and let me stay with my friends without time to arive at home since I turned 18 cause since that I am not underage.

The thing is that despite our argues, despite our offensive and bad words I do love them, (it is true that I have so much better relationship with my mom rather than with my grandma) but I do appreciate all the things they have made for me specially since I am an adopted child, I feel I have more responsability to be thankful for what they've done for me, despite all the bad things and all the bad comments some of them really hurted me during my childhood, despite all that I love them.

But I am uncapable of showing them, I am really capable of showing love to my friends and my partner, but not my family, I can give them hugs but never last too long, but it does with my friends.

With my family I cannot do that, I know they will like it, but there is something in me that cannot do it.

And I am breaking my head trying to explain why.

Any comment is more than welcome