You lose motivation when you feel hopeless because nothing is working and you think you have tried everything, or you will never meet the right partner.
But this is an arrogant attitude that implies you already know everything or every one of the 7 billion people on earth.
A bit of humility in accepting that you do not know everything and everyone out there or something new is being created right now, or that you can come up with a new idea if you try long and hard enough, there is hope.
If there is hope, then motivation returns. It is a question of arrogance and humility as to what you know and what you do not know which will overcome the lack of motivation and give you hope.
Have an open mind, and keep looking, searching, exploring, discovering and meeting. You may be surprised what tomorrow will bring if your mind is open, because your eyes and mind work together. When one is open, so is the other.