Is the amount that was paid to the partner "out of shyness" from the expected profits, even though there were no profits and a loss was incurred later, considered haram or riba?

What you gave to your companion, if it was without a condition or custom, and you did it out of shyness, then it is a gift from you. Its nature as profit does not change its reality. The majority of scholars permit the gift of the mudarib (investor-manager) to the rabb al-mal (capital provider) without a condition or custom, unlike the Malikis. It appears there is no blame upon you for what you did, and it is not considered riba (usury).