Struggle to love my ex husband and his GF unconditionally


I have been working on unconditional love for my ex husband and his GF. The problem that I’m having is that I keep telling myself “I really don’t want to love them and I actually feel more empowered hating them”. I know this sounds awful but they did a terrible thing (as far as my values go) and I just don’t think they deserve my forgiveness and love. I understand that my thought “they did a terrible thing” is my thought and only I can change it. I think what I’m mostly struggling with is the idea that I’m “supposed” to change that thought. I understand that forgiveness and love are “my feelings” and these feelings will generate positive results…but I just don’t want to forgive them! Is it a thought error that I keep telling myself “they did a terrible thing and they don’t deserve love and forgiveness” or is it a thought error that I keep telling myself that I’m “supposed” to change my thought and get over it and love them because they are human and deserve to be loved unconditionally? Help!!!! small thought….big dilemma!