I personally just use regular KY jelly when I need it. But I don't think you're ruining your relationship. With my last pregnancy I felt really awful towards the end of my pregnancy and couldn't have sex and then of course for 8 weeks after I Gabe birth I couldn't have sex either. So no sex for like 3 months and my husband waited.
i have been the Drs they said to use lubricants but I don't know which one would be better.. Water based or silicone based.. We've never had to use them before so I don't know what to do!
I think that if he really loves you he will wait but in the mean time maybe you should talk to your doctor about it. They might be able to give you some advice.