Relationship ending

Me and my ex partner were together 10 years, we have a 17 month old boy together. I cant fault him as a father but when we had our child I grew up and he didnt. I've got over the relationship now but I cant help but feel gutted that I'm either going to have 1 child or children from different fathers. I dont have a problem with either at all but I just always dreamt that I would spend the rest of my life with this man and have more children with him and now it's gone. Has anyone else ever felt like this? Will the feeling pass?