In our case, we didn't have the option to try an OE IVF, so it was either DE or adoption. Neither of us is opposed to adoption, but after explaining to my DH just how much I wanted the opportunity to carry the child, he came around rather quickly... I think he just had let it sink in a bit, but once he saw that I was completely ok with not contributing to the genetics, he was too.
I completely and totally agree that any child conceived through DE will be 100% yours - if you provide that gestational home and you get the joy of nursing that baby, than you have a fairly large impact on that child's biology. It may not be yours genetically, but I argue that the biological link is just as strong!
Good luck and best wishes!