Well, the next time she says this in her half joking manner, tell her in the same tone that should your boyfriend not be invited then you will not be attending either.
I would sit her down and tell her point blank - I value our friendship. I enjoy being your maid of honor - it IS truly an honor. However, i don't want to hear one more word about bf and I beign engaged or getting married.
I agree. If she keeps on about your bf, then let her know you will not be going to the wedding if your bf is not welcome. If she "uninvites" him the night before the wedding, you ghost on her on her wedding day. I know it's her special day, but she can't be treating your bf like garbage. My motto is, "if you disrespect my bf, you're disrespecting me".
Like the others have said, its time for a talk with your friend. I'd start with the part about your bf not being invited or welcome unless you do what she wants (as in blackmail). If she is serious then I would bow out of the MoH role immediately. If she won't stop about you getting married on her timeline then I would bow out over that too. That is ridiculous for her to pressure you to get engaged at all, and especially as a condition for attending her wedding. (most guys would probably prefer to not attend when they heard what a crazy b**ch the bride is being).
If she keeps this stuff up you will likely be fairly angry and resentful by the time your big jobs come up---isn't the MoH supposed to host a bridal shower and organize the Bachelorette party?--and not want to ever see her again by the day of the wedding.