Scarlett, I hear what you are saying, you are going to Relate and in that short time frame, things are definitely looking more positive, which is good.
However, I would be very reluctant to take a decision about moving for these reasons:
a) If someone had a long history of being controlling and not very nice and then they got help, I would want to see evidence of their long-term change, over weeks, months indeed years before I moved my entire life for them, not three weeks
b) In that three weeks, your husband announced he was going for a new job in Malaysia even though you desperately don't want him to, including suggesting he come back every three months. I don't really see this as taking account of your needs or your family's needs at this time-point.
c) You are crying all the time at the thought of leaving, and feel hysterical at the thought, I think that deep down you know that all is not quite well in your marriage and are scared at living a long way from home with just him as your support
d) The behaviours you mention are quite worrying, not having access to the phone, or the car keys being taken off you, these are not 'communication difficulties' of the type Relate deal with, they are controlling and scary, and I wouldn't personally allow myself to be totally in the power (i.e. he will control if you have money and a car and where you live) of a man with power issues myself.
Of course it is up to you. Personally, I'd let him go first, see how the marriage is going, go to visit and take it from there if you are committed to being with him.