I'm an intp married to an entj, so maybe this won't translate well to your situation, but here this goes:
It feels like a one way relationship, where I try to meet needs, adjust my behaviour, my expectations and plans, while never feeling understood or emotionally connected.
If he doesn't also adjust his behavior for you, it makes sense that you see this as a one-way relationship.
When I have voiced my feelings of 'lack of connection' I've been made fun of, or when I say that I need reassurance and emotional engagement I've been told that I need counselling.
Being given advice by an INTJ sounds normal, but the being made fun of part is unacceptable in this more serious situation. Tell him what you have done already to adjust to him, and how he can start doing the same for you, which for starters, would be for him to take you seriously when you say there is a problem---even a problem of imbalance. Taking and taking from you is fine in theory, but there will be a point when you will have nothing left to give (even if he gives something back, if his contribution doesn't match yours, you will be at a deficit. Changing yourself, something everyone does when they grow in a relationship, does come at a cost to you, so he needs to at least see that). He has to either explain why this isn't a problem, or show what he can do to help the situation, and of course you'll do your part and consider if counseling is something you need too. You can say you will go to counseling, but he also needs to be there for you to vent to (it doesn't have to be venting, it can be whatever you think fits here) when you need it. A counselor can help, but your relationship is with your husband, not this outside person, so your spouse has to be part of the solution.
I don't like the conflict and would prefer to avoid it, but I feel like I have to stand up for myself on a daily basis.
That's my experience with entjs (and intjs too, from seeing friend's relationships) if you want to be treated on equal ground. Gotta be able to show every once in awhile that you can handle heated debate. I see it as this is what I admire about my ENTJ, so if it is directed at me too, he is being consistent with his real self with me. But he does hear it from me when it goes from practicing wit to being abusive. (he sees it as playful teasing sometimes) Also my MIL is an infj, and I tell her that when dealing with her son, I dial his intensity back 2 units in my head, so it sounds like something a normal person said. She appreciated the advice (well, she giggled, so I thought it was good advice)
Another thing to consider is if he considers these confrontations as fun and not serious.
I feel like I need to leave my relationship. But I can't.
In that case, your options are: (1) you change, (2) he changes, (3) you both change. In the end, if your goal is to stay and be happy, put your foot down, don't shy away from confrontation, and remind yourself you are fighting for having more moments when you both are great friends and spouses. Realistically, you both will probably have to change, especially since you will need to be relentlessly confrontational in the short term to get the change started. If you know a debate is coming, do your best to prepare beforehand: you know his point of view, so try to predict what he will say and prepare counterarguments.
Haha, sorry, I'm giving advice that you won't be comfortable with. So feel free to ignore this. If you are considering this advice, read it with a critical eye, especially since intp x entj isn't an infj x intj, and at the end of the day, you both are unique individuals.