Like jesse, I too hope another FTM or even another significant other can advise and support you.
I can add, that after almost 30 years of marriage, there are many times when either of us has been facing a change in our life. The other frequently feels left out.
It is entirely unacceptable.
But the reasons are invariably that we are looking for something we feel we can find elsewhere. The solution has always been for the other to make their feelings known and for us to stop being selfish.
Your partner needs to know he is negleting you, your relationship and himself.
I've done the same thing, several times. I am so, very very sorry for what I did. I really hope he is big enough to realise and feel the same.