Only when it rains

So here’s the situation...Have you ever had a friend, that disappears, whenever she gets into a relationship (that is good) and then returns only when it is not going well or over?  This can be disappointing to say the least.  I suppose it is more tolerable, depending on the friendship.  If it is framed in your mind as a friend who is like family, the kind you see infrequently perhaps it is more tolerable.  In this way my expectations are different, but it can still be confusing.  There can be feelings of flattery that the friend considers you to be a loyal friend, but an awkwardness and perhaps even sadness, that you don't place her in the same light.  Perhaps you don't need to.  

what does having a friend or being one mean?

What does it mean to have a friend or to be a friend anyway?  All relationships change and with that, maybe our expectations need to change as well.  Many would say we should have no expectations.  Sometimes our goals and interests veer far from that of old friends' and the friendship seems to cause more discomfort than comfort.  When we have had long standing friendships, often our worlds intertwine.  It can be awkward to comfortably carve out less contact in shared social settings, as others expect your past level of friendship with that friend too. So again, what makes a friend?   It seems there are at least two delineations of friendship.  The first type of friendship calls for both people to feel connected.  The second type requires that at least one of you likes and trusts the other. The difference here is that in the first scenario, you both feel that mutually gratifying feeling of giving and receiving and the second only one of you has that feeling. Past that breakdown, I guess there are qualities of friendship that should be there in some composite: honesty, loyalty, there with you when the going gets tough, there to share good times.  A friend listens to you, protects you or wants the best for you, keeps their jealousy in check, shares interests with you, excepts your faults while striving to brings out your best.  How many of those items on the check list must be checked off to still be a friend?  I don’t have an answer on this one.  What do you think?