<human>: Can you condense the text into a few key points?

We have been together since the age of 16. I'm transgender and was still a boy when we met, and continued to behave as such for the majority of our relationship. 

She has been very supportive of my need to transition and we are still best friends. However, for various reasons it looks unlikely that we can function as a married couple, and we have discussed separation multiple times as a result.

We have had no major arguments, and as we have two children, we hope to keep it that way by ending the relationship on our own terms.

We are facing two main problems; fear of change and practical concerns regarding our children. We've been through our options, but we can't seem to make anything stick. 

Does anyone have any experience of advice towards ending a loving relationship? What is our best course of action?
<bot>: Parents and best friends need to separate. We can't bring ourselves to do it and/or don't know how.