Welcome to the MAO site and thank you for asking such an intersting question.
As with so many other questions raised regarding stomas, there is no strightforward answer to this one. However, I will try to comment constructively so that you (hopefully) are not left with the feeling that you're going nuts!
Firstly, there will be some smells that are potent enough for everybody to get a whiff of and these need to be managed, either by the many methods of pot pourri potions and lotions available, or by being confident enough to admit the problem or walk away leaving the smells behind. I feel sure that your husband would be honest enough to tell you when he detects smells at this level so I will move on to those smells that only you/we appear to notice.
These come in a whole variety of different fragrances, from that generated from the output, which is usually unmistakable, to smells coming from things like mucus and body odours- down there! Sometimes these are from the stoma, other times they're from the anus and yet more times they seem to just seep from unidentifyiable parts of the body where they did not come from before.
If your husband genuinely cannot smell them, then they may be clinging to your own body and making their way to your nose without involving other people's olfactory senses. This can be disconcerting because we are conditioned to believe that everything we smell, everyone around us also gets a bit but this is not always the case.
Some people deal with this phenomenon by wearing perfume(usually expensive) all the time. Personally I hate most of it as it smells worse than whatever it is the person is trying to cover up and it always strikes me as yet another way of polluting the atmostphere but in this case it is done deliberately.
Now we come to the vexing subject of smells that may or may not be 'real'. Some people are very sensitive to what they deem as 'smell' because the sensation is experienced in the same way as smell from external sources. I don't know how many people realise that smell and taste are much the same thing in terms of the mind's perception of the experience so what may seem like smell, might be something that the person is tasting. This can be witnessed when we have eaten things and appear to smell them long after they have been digested. (of course they may still be apparent as a smell on the breath but sometimes they are tasted from within rather than externally).
From my own experience, the problem lies in the phenomenon of whether we 'worry' about these sorts things, or whether we have developed ways of accepting them for what they are and move on to be distracted by more interesting and enjoyable things in life.
'Worry' is a derivative milder form of 'fear', which is one of many emotions that would be better kept under control, rather than allowed to run riot on their own. Unfortunately, most people have grown up in a world where there are vested interests in making sure that the majority of humans do not having control of their own emotions. This allows them to be easily exploited by politicians, salespeople and those who want to dominate others. Thus, the methods and techniques of emotional control are rarely taught to our children or to adults because there is little to be gained by those 'in charge'.
When fear, anxiety, worry, etc becomes a problem, it is often portrayed as an affliction or fault in the individual sufferer, rather than a reflection of aspects of the society in which we live. As long as this perception can be sustained, then the sufferer can be both blamed and 'treated', without needing to draw attention to the underlying causes. The status quo is maintained and the money makers gain at every stage of the process.
That's my little soap-box stand but there are those who have developed alternative attitudes such as "S-it - happens! -get over it!" or "This is not my problem!" or "Don't worry -- be happy!" etc. Indicating that getting embroiled and 'stuck' in unproductive emotional responses is counter to living a carefree life.
I realise that this response may not be what you expected but I hope that you find some of it helpful