I don't think you're odd but there can be so many benefits to allowing your children to develop comfortable attachments with other appropriate adults in their life. My daughter frequently has sleepovers and it reassure me to know she feels safe and close with others in her life. I am lucky to have people I trust and who are keen to be so involved. I couldn't do it at 6mo because of breastfeeding but by around 18mo I was comfortable despite still feeding to sleep and several times over night as I knew my mum would comfort her in other ways and the milk wasn't a nutritional requirement.

What is your plan for when you have your 2nd? I know that is the one time so far I was thankful to have other adults to rely on. Even though I was home after one night my daughter asked to stay another with Grandma, it was such a bitterest moment.