Having been with someone this long and still have your relationship in question can be painful. Are you wanting to get married? Where do you see yourself in the next five years? Before waiting for this person to commit to you, ask yourself what is it that you want from life. If after finding that answer, you feel that he does not want to be a part of that future, you should be prepared to let it go.
May be he's not ready to get married. Try having a conversation with him regarding this. If he still ignores you, its time to move on!
This situation requires immediate action. Clearly you two don't want the same things from life at the moment which is not very good as wanting the same things from life is a very basic requirement for a healthy successful relationship.
You wanting to settle and get married is completely understandable from your part. Whatever the reasons maybe for your boyfriend to constantly delay it, we respect his choice. But you should have a conversation with him once and for all to give you clarity. Are you willing to wait for him? Does he need more time? Does he not want a marriage ever? Are you okay with being in a relationship with him without marriage?
You two should sit and ask yourself these questions to arrive at a consensus.