My T went on maternity leave for 6 months, but only came back part-time. Thankfully, the T I got referred to is better? I have a closer relationship with L than I did with T.
I know it's painful going through it. I'd like to believe there's a purpose to it all. I.e. - if ex-T didn't leave me, I wouldn't have found T. And if T didn't go on maternity leave, I wouldn't have found L. And T almost prepared me for L. All the work I did with T has allowed L and I to work on the deeper issues.
I'm sorry you're going through this, and it being a pattern.