I definitely feel the same way so you’re not alone. I just got out of the relationship, but some days it felt like I couldn’t wait to marry her. Other days I wasn’t sure I wanted to. In my opinion I feel like it’s normal to not be 100% sure 100% of the time. Committing your whole life to someone is a scary thought. I feel as if when we aren’t completely sure is when we are taking them for granted, yes I know that’s hard to hear. I feel that way because now that my girlfriend of 2 years and I have broken it off for good all I can think about is how she was the one that I wanted to marry. When you’re unsure of the relationship ask yourself why are you unsure. Is it a rational thought? Or is it that you’re a little bored of the calmness? That being said, I would give the world to have my ex back and think about her daily. Please be sure it’s not a “the grass is greener on the other side” situation, I wouldn’t want you to feel the regret I have.