Hi Cobie,
I also have UC and have been unable to get critical illness cover. I reckon it is just one of those things that they reckon will cost them a lot in the future. Unfortunately the statistics show that you are more likely to develop colon cancer if you have had UC more than 6 years (which I have), so the insurance companies won't insure you unless you are perfectly young and/or healthy.
Would you be better off putting monsy aside each month in a high interest savings account, so if you needed some extra if you husband was off ill, you could use that? Also, make sure YOU get critical illness cover, so if the worst happened and both of you became unable to work, you would be able to have some income. Try and get as much as you can so it could cover you both.
I do have sickness insurance (as I am self employed) which kicks in if I am off work for 4 weeks or more, but it does not include any diseases I had from when I first set up the claim (2002). So if I was off ill with Colitis, I would be stuffed. But if I broke my leg I would be okay! Your husband could go for something like that, so if he was ill with anything else, you could still make a claim.