Spouses of Transgender Community Group
Being transgender it's not easy but neither for their spouses. This group is created with the intention of helping and getting to know others that are in. the same situation or to just educate those that are on the other side of the fence and want to know how does it feel or how would it feel to be a spouse of a transgender person. The main objective of this group is...

The mood, shortness, and being defensive part might be med related, and temporary. IDK about the acting out with others. That may because his system is flooded with testosterone and he making poor decisions on top of the hot mess that's hormone therapy.
I'd try to set some boundaries and give him a few months to level out. If he can't get his mess together maybe a short break would be in order. Does he have a good support system? Can you address these issues with the physician prescribing his testosterone?
Good luck xx
He may be taking T, but that's no excuse to be a major jerk.
I am in the same boat. My partner is currently being short, defensive and the mood swings are all the time. Not to mention I am a mom and I am juggling a lot currently with being a mom and supporting my partner through their transition. Lately though it seems like my entire relationship is based on sex. If we are not intimate then we are on the road to just being roommates or best friends as my partner states. I on the other hand dont see things that way. I thought a relationship was about being there for each other being able to support each other as well as going on adventures together and so forth. Now it seems like my partner has one a track mind and the romance has just disappeared. All I do is pray things get better at this point because I love my partner very much and see my future with them.
In addition to being simply stupid juice, testosterone has a huge effect on libido, obviously I've been on both sides of this and while I've regained a strong sex drive since being on hrt for a couple of years, before my sexuality was simply compulsive. It wasn't something I could ignore in the least, just as estrogen has mmade it impossible fir me to push away my emotions.
So some ftm friends have gone very over the deep end with their sexuality. I think a part of this is, not being socialized male, they haven't learned all the ways men contrive to keep that in check.
One guy, much to the anger and disappointment of his partner was spending a couple of evenings a week in Boston's back Bay fens giving oral sex to random guys. I'm not saying this is all ftms at all and this couple had pretty spectacularly bad communication and codependency making things worse.
I would caution you about ultimatums, they never worked on me (though I was given to releasing that male sex drive on myself, not being very comfortable in my own body around others).