@Wibblewibbles .. I am so sorry to read this. I have witnessed three close friends go through something similar and they have all walked a different road.
I think I would ask for a meeting..
Say that you are very grateful for their concern and would be also grateful if they could allow you to continue to take each day as it comes and to carry on as you are. You are happy to update weekly, in private pre arranged meetings and will update should anything change. In the meantime, right now, you are getting the support you need outside from the counsellor and your own support network and that you feel that continuing to work is what you need to do right now. Repeat that you are very grateful for the offer of compassionate leave and you would like to retain the option to take that at a time in the future when you feel that it is right for you, even if that time might be after DH had died. Be very clear that you know that they are there should you need them, but for now, that you need to stay in touch with the parts of your life that you can control and that as long as you are functioning at work, you would like to keep it that way, but as soon as that need changes, you will contact him immediately. You can tell him that you have had long discussions with your partner and that he is also getting all of the support that he needs.
and dear lady, please do reach out into your circles for everything that you need. Sometimes we need to reach further out to find that person who will not look at you with sad eyes, will just listen and will do the things that you want them to do without bringing with them a load of expectations of what they need from us in return... find those people, ask of them what you need and feel no responsibilities for their feelings.
Maybe build some of that into the conversation with your boss... Dear boss, what I need from you and company X right now, is to see me as Wibblewibbles, employee, not wibblewibbles, distraught woman who is going through the most awful thing in her life, I have enough of those people around me. When I need that from you, I will let you know.