Hi there Sweet,
I think the key thing for you to do is to have an honest discussion about this with your b/f. You sound like you want to keep hold of this relationship and you should tel you b/f this. He may beable to give you a good reason for the friendship that you hadnt thought about, in the same way that you might be able to give him a reason for the relationship that he had not thought of.
I wish you luck and welcome to HealingWell!
The main thing I thought about when reading your post is the amount of love you have for your children. Its clear that you love them and I think its great that you recognise that they are only part of your happiness. However, you run the risk of holding on to them too tight and that can cause you as many problems as not holding on tight enough. As for the feelings, they will fade in time. Try taking up a new hobby or craft. Something that takes your mind off what you are feeling. Perhaps something that involves the kids?