Excessive Parental Attachment. Do his mother and father constantly direct him on what to do and when to do it? Are they his “best friends”? Get out from under this stifling relationship while you can!
Does He Still Live at Home? Unless this is a temporary solution to a recent living / housing problem or he is taking care of an elderly parent, this could be closely related to tip #1. It may mean that he is not motivated enough to get out. What would that mean to you in a long term relationship?
He never invites you over. Why? What is he hiding? If he can not be truthful about his living arrangements then what else is he hiding? There will be some serious truth issues here.
Is he Moving Too Fast? It is possible that he is looking for you (or any woman) to solve his personal problems. It shows signs of desperation and you really do not want someone that clings onto you all of the time do you?
He Just Ended a Relationship. If you have ever been through a break-up, then you know that it takes a long time to completely get over it. If he is fresh out of a relationship, he is going through the recovery process, which leaves him little time to completely focus on you. You might be his temporarily bridge to fill his loneliness, whether he realizes it or not. He is Constantly Referring to His Ex. It does not matter if he speaks highly or lowly about his ex. If he is constantly bringing her up around you then this is a serious red flag issue. He is not through with the relationship so you will just be a diversion and not a real partner.