Husband Chose Mother over me

Hi everyone, I need advice, first off my husband and I have been going to counselling for our troubled marriage for 6 months now, my husband was a raging alcoholic for 4 out of 5 years which created many issues and just this last year got sober which I am proud of him for, I work shiftwork as a nurse in a very stressful place and only get fridays and Saturdays off once in a while, which I cherish, today we had plans (sat) but that all changed last night when my husband told me his mom and dad were having an early Easter dinner as they are going to Mexico, I asked what time I should be there this morning and was given the response "you weren't invited" I asked why on earth would I not be invited! My husband then said his mother did not want me there (I have NEVER done a thing to his mother, but she has always had it out for me), I then asked what prompted the uninvited issue and he said he had no idea, I then assume he of course will not attend and will bring my son and himself home at once (they had been out doing errands all day/having guy time) as he should be equally offended, he says he does not know what the big deal is! I tell him I am offended and would like to ask his mother what I did to deserve this, she replies "she was enjoying a night with her grandson, son and friends and family, and didn't need to explain herself as it's her party", making it clear I am not one of those people, I tell her to have a nice night politely and hang up. I then blocked my husband (who called me repeatedly, but he is obviously blocked and knows that now) and I am considering divorce as this is the final straw for me and completely disrespectful and constantly happens in one aspect or another with his mother, he has obviously chosen his mother over me and this has been going on for years now with no change. Tonight was the most blatant and honest thing she has said to me which is I am obviously friend nor family and my husband is not seeing anything wrong with this. His parents are always trump cards in his life and it seems I have no business in this marriage anymore. Advice?

Also just to add injury to insult, I just had a major loss of 2 family members being murdered in late December and have been going through a particularly stressful and sad period and never got a single condolence from his mother! Knowing how fragile I am right now this seems like a particularily cruel move on her part.

Thanks everyone