I have 3 children 10, 8 and 4. When my eldest was born, I reduced my hours at work to 4 days which worked well. Several other parents have done the same. My colleague is returning to work from mat leave and has been offered a day off but its a Wednesday as they can't cover any other day (customer facing) and she was complaining how other members of staff have had the more desirable Mon/Fri off for many years and they should give that up for new parents. She wasn't talking directly to me but I felt she was annoyed I wouldn't give up my Monday off because my children are 'grown up'. I feel that I have built my life around a Monday off and have so much going on in the week running around after my kids that I still need it. Moreover I have no plans to return to full time as I enjoy the work/life balance and we make financial sacrifices to allow this and I am on a permanent 4 day contract.
Am I being unreasonable to not give up my day for her?