Thank you for your query.
If your husband is diabetic, and you are sexually active without protection, increased sugar levels in the seminal fluid can lead to vaginal infections.
protection is advisable.
But that could not be the reason for abortion, unless there was intra uterine infection
, rubella , herpes etc.
Also, there could be other causes like genetic causes, autoimmune conditions, hormone imbalance
, medical diseases like diabetes, hypertension which you might be having, uterine abnormalities etc.
You need to have detailed evaluation , as one cannot pinpoint the cause so casually.