Generally, if someone is meant to be in your life they are, without any effort on your part. If, however, it's a matter of wanting them there, and say maybe they aren't good for you or are keeping you from going along another path that would be better for you personally, you may find have to impose your will to keep them there or surrender it entirely for them to stay.
I would suggest a good litmus test here would be: Where does this relationship fall on the 'Drama Scale'? If it's high (lots of drama/lots of work) then that's probably not a good indication for longevity, but if it's low (no/little drama/work) it may be that you will eventually have this person in you life when either THEY or YOU are at a place that you can meet as equals and grow TOGETHER from there.
Everything does not happen in 'our' time-frame, sometimes situations, like fruit, have to ripen before they can be enjoyed. But, do remember, IF this is not positive for you, the road-blocks you keep encountering may be trying to tell you something: listen or you may end up suffering for it. You have to decide which is the case.