Relationship anxiety

I need to some with my relationship anxiety. I'm 27, soon to be 28, and I just don't know how I feel in my relationship. He's a WONDERFUL guy and treats me very well. He's OK just dating for a while, but I'm worried if I don't date around more, I won't know if I'm just anxious about marriage in general, or if it's something with our relationship that I can't quite place. We've been on and off for two years now and I'm trying to figure it out in counseling once/week. When we're broken up, I feel extremely depressed and like I've hit rock bottom. All I could think about was how to get back together with him because I realize I was taking him, and all his great qualities, for granted. When we're together, I feel nervous and scared because I'm not sure how I really feel. Some days I feel like I want to marry him and some days I feel like I just want to hang out with my friends and not think about serious stuff. Can anyone offer any advice? My goal is to feel calm and relaxed, and happy. I don't think relationships are supposed to make people feel this confused. I don't know. Am I just a perfectionist who is going to feel disappointed with anyone and everyone I date? People say they "just know" when they found the person they want to spend the rest of their lives with. I feel that too - some days. Other times, I'm not like 100% sure. Do you think if I keep dating him, I'll know eventually know one way or the other?

Thanks, SC

Is it possible to be half in and half out? Like I enjoy going on dates with him, but maybe I'm just not ready to make that big commitment? If so, it seems unfortunate to call it quits if I really like spending time with him, but it's also hard to just stay in one phase of the relationship without plans to move forward. It's so frustrating.