Can I stop the dental implant procedure after the bone graft?

I had a tooth extracted and a bone graft done approximately 6 - 8 months ago in preparation for a dental implant. The graft is completely healed but I am contemplating not moving forward with the implant rest of the procedure due to monetary reasons. My dentist has just told me that I do need to move forward with the implant as there is a potential for the bone graft to deteriorate if I wait too long? Is this correct or can I just stop at where I am in the procedure?