I'll try not to make this too long...I feel like I'm too close to the situation and can't see the wood for the trees.
Strained relationship DM, fairly good relationship with DF. DM and DF have been divorced some 25 years. Very amicable and been best of friends since. Both have remained single and have continued to spend every Christmas day together,
Have one younger DSis. We have not seen each other in 3 years and have had minimal contact in this time. This is due to her behaviour towards me in the past and some unforgivable things she has said to me, She is very reliant on my DP's, both financially and emotionally. This has always been the case.
DP's generally take turns with spending Christmas day alternately with me and DSis. There have been two times in the past 2 years when they were supposed to come to me but dropped me quite last minute to spend it at my Dsis's
instead. This year it has been arranged for both DM and DF to come to me on Christmas day. DM has now asked that I allow my DSis and her two sons to come to. I said I wasn't happy to do this given our very strained relationship and the fact we haven't seen each other for 3 years.
Then came the emotional blackmail by my DM. My DF has a life limiting illness which means he has between 1-3 years left depending on how successful treatment is. DM told me I should invite Dsis for xmas as 'it may be your dad's last Christmas'. I am disgusted she used this line as DF would never dream of doing this. For the record, Christmas does not mean much to him and he generally goes with the flow and whatever is easiest.
The thought of having to have Dsis here is filling me with dread. What I be a completely awful person to put my foot down and say no?