Hello and welcome to HCM!
I read your story very carefully! The fact that your husbands' moving sperm is less than 50% then your doctor is right to suggest you go for an IUI, meaning artificially placing the washed sperm of your husband into your
uterus in order to increase the chance of
pregnancy. Since you already had an
abortion it means that you are able to conceive and maybe the low quality of husband's sperm is the problem. Therefore, IUI seems the best option for you.
As regards the rhesus issue, yes, you should be vaccinated against anti-rhesus
antibodies but this is done once you are pregnant, usually at week 28 and 34 of pregnancy, in order to protect your second baby. Therefore, you need this only if you plan to have a second child since non-
vaccination is not harmful for the first baby. However, if you are pregnant then the medical staff will definitely remind and suggest you to get vaccinated regardless of your attention to have a second child or not.
Best !