I think it's unprofessional to be posting like that while at work. Text a friend or family if you are bored, watch videos, whatever. It comes off like soft soliciting to me.
I think both you and bf have some inappropriateness when it comes to social media. He very obviously has a jealous streak and reading that past thread, double standards at play.
But no you shouldn't be posting like that and accepting money.
If he had come and brought snacks, drinks, whatever to thank you that's fine.
Just my opinion.