Even if you get him neutered...it can take up to 3 months for his hormones to settle down...you will have to address his territorial issues...beginning now! You don't want this behavior to continue for the next month or two or it will make it harder to deal with if he gets used to bossing his humans around! It is very fixable though.
we have all gone through something like this at one time or another to some extent!
I would suggest restricting his "out" area...sometimes bunns can get aggressive or territorial if they have too much "area" they have to defend. They get paranoid. Your DH doesn't have to "do" anything...just be in the wrong place at the wrong time! Even seeing something out of place, like a dangling finger for instance, can set them off!
Its not personal.
Try to restrict Gizmo to a smaller area...don't let him roam the whole room...he can have "out" time but restrict it to a smaller more managable area. Keep working with him with the gloves on correcting any aggressive behavior...thismeanshubby too...and make sure you are both correcting Gizmo the same way so it is consistant.
Checkhis area too...has anything in his environment changed? Change can be very stressful for bunns!
Are the windows open now where they were closed before? New sounds and smells could be setting him on edge...increased foot traffic in his "area"...
Restrict his "area" for now...and once he is neutered and has settled...slowly start to expand his "area" again a bit at a time.
I have been on the receiving end of bunn bites...I don't think your bunn HATES anyone. It is usually because the bunn associates one personwith being in a position of authority and the other is not! My hubby gets bitten, nipped and lunged at more than I do...which is unusual because he is the "guy" who distributes greens every night and fills the food dishes and is the bringer of treats...so he thought he was "the man"...what he is...is a heck of a lot quicker! lol
Bunns will use nipping and biting as a corrective technique. It is what they would do to another bunn to discipline them! It is just unfortunate for us we don't have a thick coatof fur to buffer the damage a little! So they will use it on you too! Nothing personal...just training you!
Danielle