Cancelling wedding

My fiance and i are suppose to be getting married in 2 months time, we have a 8 month old daughter together and i have a 10yr old son from a previous relationship. Our wedding is overseas so our guests have already booked there flights and accomodation already, deposits on the villa and vendors have all been paid, my hens night is in less than 6 weeks and my bridesmaids have all paid for that.
Our daughter was born 11 weeks early so right from the start iv been dealing with alot, and the last couple weeks its hit me like a tonne of bricks i felt like fiance didnt show much interest in the wedding, i feel like i possibly have post natal depression, so iv booked in to see a therspist to help myself, but fiance wants to postpone the wedding and says cancel it but stay together until were happy again. Im so heartbroken i just dont know how i can stay with him after this, on days i was feeling down id think about how excited i was to marry him and become his wife, the feeling id get when id picture us standing at that aisle made me so happy..... now i no longer have that.
If hes not happy or cant c himselc marrying me then i 100% dont want him too, but he cant understand why i cant stay with him, i have things arriving daily in the mail for thid wedding, i feel like its opening a whole new can of worms by cancelling but staying together, if he cant love me at my worst how do we get through this? He said we might get married again one day, we have a beautiful daughter together but hd still cant commit to me? How can i trust one day years from now he decides ok hel marry me now but doesnt changr his mind again. For me marraige is a lifelong commitment lf two people who love each other, i only wanted to do this once, he wants to stsy engaged just work on our happiness, bt everytime i see the ring i think how could you propose and claim u love me so much but cancel so close? All our family and friends whov spent so much money to be there. I just feel so hurt, humiliated, ashamed and 😭