advice or just someone to listen

Hello everyone, I'm 52 years old,been divorced for a year,my ex still lives in the matrimonial home with my son 17,no one else was involved with the break up,just basically two people who weren't meant for each other,tried for years to make it work but in the end we had to accept we were both desperately unhappy. The children ( one 24 ),were poisoned against me,no contact since the divorce,I decided even though we were lucky enough to have a large house,it could of been sold and provided two houses easily,the idea of my son leaving home before he was 18,was not an option,my ex sent a text the other day," don't be selfish,let us stay in the house till the kids want to leave " what happens if their there for another 20 plus years, I'll be in my 70s, life might as well be over,pretty hard to plan the future when all you have is a spare room in a relations house.