OP, I've read through all your posts but not all the replies.
I think you should get this thread moved to Relationships or start a new thread there, with a summary of the main issues and not just the birthday question. I think many people are just going to respond to the birthday question without reading all your posts and considering the other issues in the relationship. In a healthy relationship, it would be strange not to want to celebrate your birthday with your spouse. In this relationship, which is not at all healthy, it's completely understandable that you don't want to.
I think it's great that you've decided to get counselling for yourself and hopefully it will help you to work out how you feel about your husband and what (if anything) you want to do.
Can I suggest that you read through all these comments, imagining that your sister or friend has written them about her husband - what would you think?
he's quite a negative person in terms of outlook and I'm someone who is naturally positive but my mood is very affected by the people around me. So being locked in a home together with him for extended periods over the past 2 years was quite draining. I find that these days I only laugh and feel like the old happy me when he's not there.
my husband moans and drags his feet about anything remotely "girly" that I used to enjoy (such as shopping, romcoms, doing my hair/makeup to get ready etc)
A date night with him would probably consist of him ranting about politics how the country's going to shit. I'd rather not.
He's a half glass empty kind of person (e.g. if I want us to go on a day out anywhere as a family he'll insist it's too hard, the kids will play up, there'll be too much traffic etc. and then when we're there he'll be wanting to go home early). He also can have a short fuse and can be a bit shouty when he's stressed (whereas I am more laid back) - ultimately harmless but it means home life is not exactly relaxing.
we never laugh together anymore - I don't find him funny or fun.
I don't really go out that much. But when I have done we have had some arguments over him checking up on me all the time.
I actually went out with just one of my sisters for my birthday a few years ago and he was so moody about it the next day that it wasn't worth it.
he also dominates the conversation so he really does change the dynamics of a gathering (think speaking 90% of the time).
If he loses his temper, does something wrong, or life/accidents happen, he'll always blame me or the kids.
When our other son was admitted back into hospital for malnutrition as a 2 day old newborn, his first reaction was to tell me it was my fault for choosing to breastfeed.
there were a couple of red flags while we were dating that I ignored (such as DH accusing me of wanting to cheat on him with a colleague at a work event because I'd invited said colleague to head elsewhere for drinks with a group of us, and another time getting angry and shouting at me in front of his friends at a wedding, which they told him off for).
He sounds negative, critical, controlling and rude. Abuse can be more subtle than physical aggression or verbal name-calling. I think he is abusive. Either way, he is not making you happy - quite the opposite, in fact. Think very carefully about what you want your life to be like, and what you want to teach your sons about relationships and how they should treat women. You don't want to end up like your MIL, with your sons behaving like your DH is.