...when they were never really yours. you loved them SO MUCH... but u know you cannot be together... everytime you think of them your heart hurts...you see them every weekend because they are related to you...there isn't a hope in hell you can get together... 
how to calm the heart down? how to stop it from hurting? practical advice please...
salam alaikum,
dear sister firstly i'd like to remind you one thing... no soul knows what will happen the next min let alone year two years etc, you say you know you cannot be together... how do u know? how can anyone know what Allah swt has planned for us?
im not saying this to give your heart some hope that maybe you two will be im only saying cos WE DO NOT KNOW! Only Allah swt knows.
so maybe you will be together Insha'Allah and if you dont then it is for a reason and that reason is that this guy is not good for you and that Allah swt has smething much better planned for you it will not seem so now cos that is how we humans operate during pain especially heartbreak, we get into despair and think our lives are over.
NO you need to remind yourself its not over, everything happens for a reason and it always happens for the best Allah swt never burdens a soul with more than it can bare believe you me, i am talking from experience, everytime i think that things will get better it just goes and gets worse again but somehow from somewhere inside me i get this strength that i thought i never had and you know something this too shall pass cos it always does.
healing of the heart, the heart is only healed by Allah swt, just like He brings pain to it only He can heal it. so by you thinking that maybe if you get married to this relative of yours and have him for the rest of your life your heart wont hurt no more, lol well sister im sorry but your wrong, your heart will still hurt even if you have him there by your side day in and day out, without remembrance of Allah swt how can any heart heal?
the Quran was sent as a mercy and healing to mankind so read it as much as you can, once i went to the masjid, to have an imam do ruqya on me cos i was so down, i bumped into a older muslim sister who adviced me to recite surah rahman, surah yasin and al fateha.
the Qur'an is a healer itself, it is always adviced to recite the Quran in a low voice loud enough so that yu can hear it yourself.
stay steadfast in prayer, salah is the purification of the soul.
make loads of dua but bare in mind that the duas of those who strive hard for Allah swt get answered faster, seek refuge in Allah swt from depression, despair, sadness, restlessness, anxiety and ask Him to heal your heart.
as regards your relative, avoid him as much as you can i know its hard but trust me its the easiest and better way, no need for you to be cold to him or horrible, just avoid him.
a times when you remember him and start to feel sad, get up do your wudu and pray 2 rakah nafl, then engage yourself reading the Qur'an or doing dhikr not only will you be engaged into doing something but it will be somethng that will give your heart peace, rest and make your imaan really strong Insha'Allah.
and i'd like to remind you one other thing, when i used to feel the way you do remember one thing remind yourself of people that have no food to eat, orphans with no clean water to drink, who die of fatique and hunger, what your experiencing is just heartbreak, instead of getting into despair thank Allah swt for everything He has bestowed upon you.
this life is nothing but a test, ask Allah to make you patient and steadfast, ask Him for strength and i promise you He will answer your duas Insha'Allah.
I pray He does, cos i've been there myself but you must know that this wont last forever but if you let it then it will, its in your hands who you turn to to heal your heart. The only way it will be healed is ny turningto Allah swt.
ma salama