I don't know what advice to give, but one thing I have discovered is that things usually do not change on their own. You need to change them somehow.

What I can tell you is that my heart doesn't reach any sort of low when I'm not around my yf and never has. I may miss his company or wish he were with me, but I couldn't describe that as "my heart sinking to fresh lows".

If your happiness depends on the presence of another individual, then that is a problem that has absolutely nothing to do with the BL experience. It's a problem you would need to deal with whether that person is man, woman, boy or girl. What you are feeling are not BL feelings, they are feelings common to all orientations and you need to find some way to deal with them. Otherwise, is your plan to be depressed during periods when you do not have a yf? That can't possibly be a good plan.