Cathy
I've just read back through all of your posts in case I've missed something and, to be honest, I find your situation heartbreaking as you seem to have backed yourself into a corner from which you see no way of extricating yourself. However, as I think you realise, the only person who can get you out of this predicament is
you.
I'm no expert but you appear to be exhibiting the signs of clinical depression; if this is the case, then you need to see your GP as a matter of urgency and open up to her (the use of the female pronoun was deliberate here as I think you need to see a female doctor for this one to help you open up on the underlying TG issues). Remember, even if this is the same doctor your wife sees, the doctor is bound by strict confidentiality rules and cannot discuss your issues with her. If the doctor is any good, it will put you on the path towards therapy; if not then find another doctor. This issue is critical for you and the longer you leave it, the worse things are going to get for you. Also, you do not need your wife's permission to do this!
Parallel with this, you need to address the situation with your wife. You have a few options:
1. Go 'stealth' - in other words lead this side of your life in secret. I know that you have already explained the difficulties of this but I know that many others on this site have lived similarly for periods of time and I'm sure there will be plenty of good ideas to help you.
2. Tell her what you are doing but don't seek approval. This one will undoubtedly make living at home unpleasant but I think it is anyway.
3. Tell her your plans and seek her approval via compromise. You've already said that her idea of compromise is giving you no concessions at all but, as I said on a previous post, you do have a number of bargaining tools that can help you.
4. Leave her and live your life as you want to. Self explanatory and here you have a simple decision - which is better - to suffer with her or live as your true self without her (not forgetting all of the other issues that come from a failed marriage which have to be factored in to the equation)
5. Carry on as you are at present. I'm sure this is the least acceptable option to you but, unfortunately, unless you take action, this is the one you're stuck with.
You also said in response to a previous post that you're not really sure what you want. Clearly therapy will help but, in addition, I think you should look for a TG makeover salon near where you live and book yourself in for a session. Firstly, this will help you overcome the image of a 'lardy bloke in a dress' that you currently have of yourself and secondly, when it's time to change back, you will better understand the emotions you feel at having to leave the female side of you behind (in other words, are you comfortable with resuming your male persona or do you feel that remaining in the female persona is what you really want). I'm sure you could engineer a day off to achieve this without telling your wife.
You have your daughter to consider of course. Inevitably, the existence of children in the family may have to modify what we do; for many this means that they put thoughts of transition to one side for the sake of their children but, remember, this is the 21st century and you live in Britain where there are discrimination laws on your side. If you were to decide to transition, there is absolutely no reason why you could not be awarded full custody of your child. Granted there are all of the other issues she would face having a TG parent but many do this successfully. Equally, if you find that periodic crossdressing satisfies your urges, she never needs to know.
To close, I sympathise with your plight a great deal but, equally, can see that you are prone to make excuses as to why you can't get out of your current rut which, in all honesty, in the primary reason you are currently unable to move forward. In five years time, it would be great to look back and see how Cathy has blossomed and grown into a self assured woman at peace with herself (regardless of whether she's a full time or part time woman) but for us to do this, you will need to take charge of the situation and not allow others to put you down.
I wish you well and hope that you are soon able to move forwards towards the inner peace you so desperately need.
Amanda
p.s. I'm sure you've already done so but, if not, read the following thread which now runs to 41 pages and describes a situation very similar to yours:
https://www.susans.org/forums/index.php/topic,133631.0.html