My partner and I have been together for two years now and I’m still finding myself battling to be accepted by my mother in law. 
Context for this is a bit of a long one so I’ll try summarise as best I can. 

My partners dad passed from heroin related illnesses when my partner was 17.  His mother has only just come to terms with this, 9 years on. My boyfriend is an only child and we both feel as though he’s babied a lot by his mother. They both between them have had a lot of losses in their life as have I ,but I was made to move away from home at 16 to start a life independently. 
Two years ago I moved in with my partners family as I had no where to go but made it clear I wasn’t comfortable in sharing a house with them as I have been independent for over 8 years. She took some offence over this but doesn’t want to confront this with me and it just feels like hostility towards me. She’s an alcoholic so any explanation I give is forgotten. 
She often asks me to get my partners life in order and asks me to push things such as admin related stuffs and getting in touch with lost family members etc. - I’m struggling with my own personal issues like immigration status etc and it’s just a load of responsibility that feels like a mothers job??? Not a girlfriends?? 

she also never asks about my own personal life and any life decisions I make together with my partner is greeted with criticism and more hostility. Two years on I’m a stranger to her, she knows literally nothing about my past or aspirations. 
We recently decided to move cities after living in our own place for coming up to two years and it’s just really upsetting not to have any encouragement (as I have been accepted to study nursing!!! A long life dream of mine) she never even congratulated me. 

So this brings us up to date- a few weeks ago we were told that their dog needed to be put down, she’s arranged this on a day she knows I always work. I became very upset over this as I want to be there for my partner and feel as though I’m a part of the family enough to have involvement in this ?
She never remembers any conversations we have as she’s always drunk past 4pm so trying to have a conversation is pretty much pointless , she’ll just forget it the next morning. Frustrating when you’re trying to create bonds. 

I don’t have a support network of family so find this all very confusing but gives me a lot of vibes of isolation and exclusion. It’s making me very depressed and unhappy. I attempted to speak to my partner about this last night but I was just told “my mum doesn’t make you feel like that”. Gaslighting vibes and defensive behaviour towards his mother. 
At this point I’m sick of feeling like I don’t belong and brings up a lot of past trauma. I make effort to speak to her and I’m always upbeat and ‘ happy’ to see her every few weeks but it’s just become a futile endeavour. 

I don’t know if this is jealously I have that my partner has this close relationship with his mother and I don’t, or resentment towards my own mother??? Ughhhhhhhhhh. Please help.