<human>: Condense the text into a few key points

Basics: I'm 21, he's 26. Been together almost 3 years. He still lets his mother dictate what he does and it's hurting our relationship.

What made me realize this:
Recently, he asked me to go on a road trip with him. I've been desperate to get out of town, and one of the stops will be New Orleans, I've been dying to go for a few years and he knows this. 

I said yes, i'll go with him. Then a couple weeks later he comes back and says that I can't go. It turns out that his mother doesn't want me to come because he pays too much attention to me. Last couple trips we went on, apparently his mom felt ignored just because he'd come over to me and give me the occasional kiss or hold my hand whilst walking. A majority of the time I was on my own, which I was fine with. 
So now I can't go with him on a trip I was already invited to because mother said no. I don't mind it being a family trip, I have no problem with that. It's just that he already invited me and got me excited, then let me down hard. 
We've been together nearly 3 years and live together. His family is like mine. It hurts...

This isn't the first time I've been let down by him. I don't know what to do anymore.
I love him, but i'm tired of being walked on and my feelings ignored. I talked to him about this, but he just shrugged his shoulders. I feel i'm being taken for granted. I've already written him a letter about it, I don't know what else to do but leave. I love him, and I want to marry him...I don't want to have to leave, but I don't know if I can keep this up anymore. I'm already sacrificing so much to be with him. Help?
<bot>: Boyfriend's mother dictates his actions, it's getting in the way of our relationship, and he's emotionally abusing me without intending to.