My solution for new, badly behaved dogs (granted, that experience is limited and so far, my 1 and part-time 2nd are really not that badly behaved) is to keep them contained - that means tethering to a person when "loose", crating in the house or tethering outside when not tethered to a human. Then decide on the one behavior that is most troublesome and address that intensively.

For me, with both Archer and Ami, it was the 1000 mph plow-into-me-like-I-was-a-husky thing.

With Chloe, it sounds like her play is too rough with the other dogs? I guess what I would do, is let her play with Flex until he says "enough" and then back to tether. While on tether, I would allow a bit of interraction with the little dogs, when Chloe starts to get rough, I would say, gentle, simultaenously with stepping back a bit (not jerking her, just a step or two) and petting her at the same time. Really sounds like Chloe just needs training and socialization - maybe an obedience class? I would work towards calming her, keep my voice low, play low stimulation, not getting her super excited.

As for keeping your sanity and not killing your fiance? Smile to yourself and keep telling yourself what a wonderful, compassionate, kind-hearted individual you chose - the knight in shining armor who will be savior to those in need...

And long walks/runs by yourself to blow off steam.

Or, as DIL does with my younger son..."OUT...OOOUUUTTTTT!!!" with a loud voice, a pointed finger and planted feet. Which is why Josh so frequently shows up here unannounced