Ask a guy who is nearby who is about your same size for a spot or assist.
For motivation you apparently need to have a paradigm shift in your thinking. You are not working out and growing to please someone else, you are doing it for yourself. Your motivation should be to see your changes and gains.
I don't go to the gym for the purpose of chatting up guys in the locker room, so not having someone there when I'm changing clothes is never an issue.