was it an actual promise? or an i'll help you out type thing? if it's an actual promise then in my personal opinion yes it should be honoured particularly if he is in a better financial position than you.

its a shame because often when r/ships end things can become bitter and people think what the hell he said this she did that,he's got this, she owes me that! etc and promises and the like can easily fly out of the window

im not saying it's right but we're only human after all and we're all likely to go back on our word at one time or another whether we like to think we will or not, and if your ex Master should happen to be feeling a little of that right now then maybe it's worth waiting a while until things cool down?

either that or dont be quite as subtle and polite and point out that as he has always being proud to consider himself honourable and a man of his word that maybe he might wish to live up to the standards he has set for himself!