I am trying to visualize myself in a happy relationship, but pictures of the ex keep coming into my mind. I guess the feelings I still have for him are standing in the way. It takes time, but I'll get there!
AF.
Manjari has a good suggestion. I also had this trouble of separating "happy thoughts" from someone in particular. I found it helped me to picture myself happy and doing many of the same things without anyone, so that "happy" was independent of anyone else in things other than sex or company. Now i think it is easier for me to imagine being happy with someone else, because happy feels more like something i generate, than something that a lover generates for all things. It's a process. I still sometimes think of the past person automatically when i reach for happiness, but it improves.