Pick somebody you like. Tell them you like them. Don't over do it. You don't like them THAT much. Recognize that of God in them, as the Quakers say. Spend some time with them. Officially befriend them. Hang around them.
Marry them or move in with them. Find that there are moments when you are not appreciated, not liked. Find moments when you don't like the person you liked. There will be such moments. You don't have to manufacture such times. They will occur.
When the person you like isn't that loveable, or the person you like disdains, disrespect, dislikes you, or both of you are down on the other, pause. Retire to a neutral corner of the ring. Gather your wits. Look at the other person. Notice the sweet curves. Smell the nice scent. Listen to the excellent voice tones. When you can feel a little glimmer of appreciation for them, take a moment and reflect on the good times you have had together. Remember the other fine people that let it be known that they could see being your friend's partner. Yes, review the luck you have had.
See paragraph one. Renew. It is not so much endure as it is refresh, renew, re-grow. Repeat as necessary.