I have very much the same problem.
My new pup Ichabod is XXplayful, and constantly goading My Female Becca to play. He also attempts to involve Her in other amorous actions, which I didn't anticipate until he was more mature (he's just over 6mo now). Glad Becca is Spayed, or I'd have a house full of Pups by now.
Fortunately, I have several large spaces, where I can isolate/separate those two until I get back. I will continue that until Ickey calms down
(if he ever does)
However, when they/we are together, I allow Becca to "say" when She's had enough, and don't intervene when She gives Ickey a good nip on the neck, to back him off. I do however give Her a little pat on the head and say "good girl". She must understand that She has my support in such matters. I am a consummate enforcer of Pack/Pecking Order with my guys. Greet/pet/feed/treats...Sneakers first, then Becca, then Ichabod.