When is the right time to propose after heartache in previous relationships?

i have been with my current partner just less than a year, and i want to spend the rest of my life with her. we hav disussed buying a house and our plans for the future. her last relationship was a long one (6yrs) and she was married, they split as she was cheated on and eventually got divorced. so she is wary of marriage as they only got married a bit before they split. i too was engaged but luckily i found out about my ex partners cheating just before i got married so i too am wary about it!! however when i first met my partner she said there was no way on earth she would ever get married again, but a month or so ago she sent me a text saying she knows she said she would never get married again, but she couldnt say that she would never marry me cos she would! so this tells me that there is a good chance we could get married, thats alright knowing that but i dont know wen is a good time, or how to go about proposing. should i wait? i dont want to bring back the heartache etc?