Thanks for the reply nycindie.
He and I have talked about it in the past, but at that time, she was unresponsive to any physical affection from him. Now she appears to be initiating it somewhat.
It's selfish but part of me is happy for him because I know he misses that aspect of his relationship with her, but the other part feels threatened.
I'm hesitant to revisit it with him again for fear that I appear high maintenance or selfish. I'm neither of those things, but sadly I am a little insecure about it.
I will have a conversation with him about it, again, and he will try to ease my mind... but I can't shake the feeling of jealousy I feel when she now rests her head on his shoulder or rubs his arm or leg when for the last 15 months she's barely stood within 5 feet of him.