If any of you are unhappy in a relationship, or if you've been contemplating to leave for more than a few times, or if your friends tell you 'I don't think he's good for you', then stop sticking around.
Do not worry about whether you'll find someone as 'good' as him because you'll meet someone who will love you better than he does. Do not worry about the loneliness and the pain after a break up because that's just going to make you stronger.