For me, holding on to attachment between sessions has been a major challenge. This isn't just a problem for me in therapy though
.i struggle with love and attachment generally.
For me as I have grown my internal sense of being a lovable , valuable person the attachment issues have lessened. I no longer feel like I need to earn love so I can just rest in it. Also as my spirituality and understanding of healthy human behavior ( as opposed to how I was raised which was abusive) has grown I have come to believe in the Infinity of love. The more one loves the more one is capable of loving, so love is not a finite resource I need to fight for my share of. I believe my T has enough love for everyone including me.
My T has been exceptionally generous in terms of outside contact, touch, words of affection etc which for me was very helpful.in the end.
In the early stage my attachment was very painful, but I came to understand a lot of that pain was due to the unhealthy thought patterns the abuse created in me .(,for example if something made me feel loved I'd act like it didn't matter to.my T because in my experience wanting something was the fastest way to have to taken from.you forever. But then I'd be hurt that my T didn't do.the loving thing again. When I finally realized it was safe to just say " that made me feel loved..please do it again" and my T would do exactly that it was magical).
As I've worked on those false beliefs my attachment has become more nourishing and far less painful.
Also.my Ts love led me to begin believing I really was lovable and it turns out the most important key to healing is loving myself and believing u am worthy of love.
So.my therapy really has followed the "reparative experience" model they discuss in attachment therapy, and my attachment to my therapist ( and her reciprocal love) has been a key component of my healing