Confused/lost/advice

I've been in a relationship for 3 in a half years with an amazing guy. He has always been there for me no matter what, always treated me extremely kind, we met at work when we were both teenagers/were close friends but he wanted to date me and I never gave him a chance at first because I was going after guys that turned out emotionally/physically abusive(didn't know until after a year or so into dating them, go figure) he helped me get myself out of one of those relationships ( I was too scared and very dependent on the guy, isolated) I knew the red flags from a prior relationship but couldnt convince myself it was happening again. So he helped me get myself distanced and break off the relationship with that guy which I'm extremely thankful for him for everything/ended up getting closer to him and loving him more than anything and decided I was stupid for never giving him a chance so I did. Now to present time, the past year we've been having a lot of miscommunication, I feel misunderstood and when I try to talk deeply with him about things it seems were not on the same wave length and it results in me feeling extremely alone even though I have someone right there. I feel like you shouldn't feel that way because your S.O is gonna be the only consistency in your life. People come and go but that person stays so not being able to understand each other really affects things. I told him how I felt and he doesnt see it the same way no matter how I explain