First I want to say how sorry I am for your loss. I can't even imagine the sorrow that you and your DH are feeling - not mention the physical trama you have been through. Your family will be in my prayers.
It can be challenging when you both are in different places. Making the decision to pursue adoption instead of continuing IVF would be difficult. I can only partially understand - we have not come to that bridge in our journey yet. I think you are wise to wait a few months before making any decisions. I think the pain of losing your sons is too fresh still. Only you can decide what you are willing to do - and in marriages I believe that with major decisions the 'no' has to be the final word.
Lots of hugs to you
and I hope that you find the support here you need. You might want to try search the adoption and IVF forums to see how others handled this decision.