I'm actually on the fence about this terminology, myself.
On the one side, I detest the idea of going in "stealth" because it sounds as if there's a hint of shame as to what you were once before. This is obviously quite an assumptive observation, as that may not be the case at all. But when I hear people actively say this, that's generally where my thought process goes. You don't like who you were before, and you don't want people to make that connection...so you simply just elude it as if it never existed.
On the flipside, however, I also am inclined to say that, like a person's sexuality, that who you are is absolutely nobody's business but your own. You shouldn't have to disclose that you're transgender, in stealth mode, or whatever you want to call it. If you identify as a female, then you're a female...not a MTF. If you identify as a male, then you're a male, not a FTM. Having to classify yourself otherwise sounds more like a crutch because of close-minded people, and having to disclose that you grew up in a different sex can be quite damaging if the result of that disclosure turns negative...as if your decision to be more of yourself was a bad one.
And no, you're not obligated to tell anyone that you don't feel comfortable telling. It could be argued that you should disclose it to a potential partner because you shouldn't lie to them, but if your partner really loves you, they'd be looking past what you "used to be" and are looking more at who you are at that moment.
So yeah, I'm a bit on the fence, but I usually just agree with the person's own choice on the matter. It's your body, your life, so it's your decision in the end on how to approach it, and I support whatever choice that you make.
And on that note, excuse me while I go into a bit of a...I guess ramble, as I couldn't think of the word I wanted to use.
Basically, I treat it the same as I do "coming out" versus "staying in the closet."
I don't potentially agree with hiding who you are or what you're into, especially if you're getting married to a woman while hiding the fact that you're clearly only attracted to men. That's both damaging to yourself in the long run, and is also unfairly damaging your female partner since she's going to feel like it's her fault, or she'll just grow to resent you for not being true with yourself.
That being said, I know that there are demons that people have to fight. Both with themselves, and with narrow minded people out there that choose not to understand what I'd usually consider basic things about a person. I understand that there are people that react negatively, and even violently, to those same things that they don't understand, and there is always a risk of danger of potentially running into that violent person when you're one of those people. My parents worry for me every day for that reason, and I won't lie and say that it doesn't cross my mind that I could be jumped or attacked or beaten or worse by someone simply because I have an attraction to men. I've been called the F word a few times, and I'm just waiting for the day that it turns from being emotionally hurt to becoming physically so.
However, I do also believe that you shouldn't have to hide who you are. You are who you are, and if people can't accept that, then that's their own weakness, not yours. You shouldn't have to cater to their weakness because you're afraid of losing them. If they can't accept who you are, then they never mattered in the first place, because they never would have truly supported you when you needed it.
You are who you are, and you live the life you choose. You're out to live your life, and they can either be a part of that, or they can wallow in their own weakness and live their life bounded by their own narrow-minded shortcomings.
If anything, I usually don't disclose unless I'm asked, and I'd imagine the same route can be taken for a trans person as well. If someone asks, you can choose to tell them, but otherwise just go about your day normally. I wouldn't shout to the high heavens that I'm a gay man except when I'm trying to make a point in a discussion, because my attraction to men isn't what makes me who I am. I believe the same goes for trans people. You're not trans, you're Hannah. I'm not gay, I'm Maxwell. The steps you make to become the person you are aren't what define you. You're not the person you are because you're trans, and I'm not the person I am because I embrace my sexuality instead of hide it. We're who we are because of all of the steps we've taken in life, not just because of one of those important steps.
So in all honesty, that's how I feel like it should be treated on subjects like that. You don't have to go "stealth," but the whole world doesn't have to know the steps you've gone through to become the more ideal "Hannah" that you've become unless you choose to tell them. All they need to know is that you're Hannah, you're the person you want to be, and you like who you are. Any specifics beyond that are irrelevant unless you choose to share them for clarification/awareness.
Anyways, ramble over, I think I've made my point.