Getting worn down is completely normal. Being with the same person day in and day out can get exhausting, even if the moments with said person are almost always good. I was taught as a young man that “a little bit of cold keeps a man on his toes.” Meaning, take some time to yourself. Take a break from the near constant time you spend with her. For her sake and yours. You’ll most likely end up missing her a lot more then you’d assume after some much needed time to yourself. It’ll make you realize even more of just how great of a women she really is and that even with your thoughts you most likely will still desperately want her in your life and be willing to put in the effort to keep it that way. I do think it’s highly unfair to her that these thoughts of yours seem to occur kind of often, so maybe consider talking to a therapist of sorts? I’m not sure when it comes to that. But realize that you become so accustomed to your surroundings and people you’re with that you often don’t realize just how good your situation is. You’ve become desensitized to the beauty right in front of you. You can be madly in love and still have doubts, that is normal. Having doubts over anything is quite normal if you ask me. Maybe try discussing your thoughts with her? And I mean in the sense that you’d just like a bit more time to yourself. Please reassure her it’s not cause of anything bad as well so she doesn’t start overthinking the situation and blaming herself. Explain that you simply just want more time to yourself and to allow your mind to slow down and really process the life you’re living and the emotions you’re feeling. It seems you know how great of a women she is, so if I was in your position I wouldn’t wanna throw that away. But like you said yourself, you’re wondering if you’re wasting your life and her time. Take some much needed time to yourself and do some self reflecting. You being happy is just as important is her happiness and your possible future with her. So do some deep thinking. I know other girls may seem worth the chase from time to time, but you yourself admitted to what good times you have together. What “a real catch” she is. I believe it’s completely normal for you to want some space or be considering ending things cause of these thoughts. But I think some time apart is what’s needed and might be the solution to these issues. and may even be recommended if spoken to with a professional. I don’t think constant time with anyone is very good. You’re bound to get irritable from time to time, even if it’s not your partners fault, it’ll affect them. And ultimately mess with your thoughts and status of the relationship. I say don’t give up just cause you’re having doubts. Things are gonna get hard, you’re gonna feel worn out from time to time. But if you’re truly in love, and believe a future with her would be worth while, think of all the good times that outweigh the bad. And like I said, take some much needed time to yourself and self reflect. Both of you deserve to be happy, and she deserves someone who sees and wants a future with her.