It does sound like he is experiencing some doubt. That doesn't mean there is someone else. He might just be going through a phase where a long term committed relationship is very scary for him. If you have to push for him to tell you how he feels then he is experiencing a struggle and only he knows why and how. Your role in this is to decide if this is worth the wait. You may find that a relationship can fail just because each person is in two different points in their life. If you can't come together then it can't work. So you have to decide how long you want to wait and what will sustain you unless things change. I would be honest with him and tell him that you need more. If he can't it's up to you to stay or leave.
Please press accept