If my boyfriend is Taiwanese passport holder how i can go about chinese visa and his invitation? THX

Hello,
I like to find out, my boyfriend in Taiwanese passport holder, currently he work and live in china , he got a chinese ID, I would like go and visit him, i am (an Ukrainian passport holder) please advice what documents is require from his side and mine as well for 30 days visiting visa, and is there extentions twice in china is allows ?
As when i called to consulate they advice to use someone other chinese person for the invitation, please advice how is better to go about this case,
Thank you so much
i am really appriciate yours assistance.