I'm so hurt I do my very best for her, he lives his life and doesn't pay for her but looks like she prefers him. I don't know how to cope with this and not to do or say something will affect her even more. Please I need some advice how to cope.
Assumming there are no other issues. I would not be worried about this. Many young children will the same thing with a grandparent, aunt, uncle, or other caregiver that isn't even related to them.
It isn't even that she may prefer her dad over you. Does she cry for a long time after he leaves? She probably simply just misses him or maybe was having fun with him or simply the transition is difficult for her. Most likely she will eventually grow out of it.
Try to make the exit with dad as quick and routine as possible. If you can make it typically the same time each time he comes by. She will get used to this as the norm. Simply let dad say at say 5pm ok time for daddy to go will see you at 10 on Monday. Give a hug and kiss and say bye-bye. Then he leaves whether she cries throws a fit or whatever. Leave her alone after until is done with crying.
It may make you feel better if you realize it is not that a child prefers one parent over another as much as it could be a change in routine.