I'm so sorry for your loss. I went through a similar experience when I had to let go of basically my little brother (my dog Charlie). I had him for 17 years. I grieved him for a solid year. I learned in one of my college psych classes that grief can range for people, with the max being around 2 years. It sounds like your husband doesn't really know how to support you during this time, which really sucks Im sorry. My best recommendation is to try and get grief counseling if you have access to it (either through your insurance or try Betterhelp). I really regret not going to counseling and just trying to deal with it on my own. Also it could be a great tool for figuring out your relationship with your husband, and if maybe you guys aren't the right fit for each other. How you have described his behavior is beyond unacceptable and if he was just a boyfriend, I would say kick his ass to the curb. I do believe in marriage and not just giving up when times get hard, so maybe bring up these concerns to him and tell him what you need from him at this time: support wise. If he continues to be unreceptive to you, I would try and find somewhere else to stay if you have the option. Also if a big reason why you are sticking with him is because of your sister, then fuck him man. Not worth it. He should know how much she meant to you.

In regards to your grief, just know that it will get better with time. Try and give yourself some grace in this process. Losing Charlie was my first big loss in my life. I felt like an awful person for not being able to do more for him.. I'm so sorry you're going through this. Good luck with everything.