Disclaimer: I Do Not Own Call the Midwife.
After the death of his wife, he never thought he would fall in love again. Never did he dream that he would fall for Sister Bernadette or that his heart would ache as badly as does now with the knowledge that he can't have her.
It's like God is having a laugh at his expense first his wife dies then he falls in love with a Nun.
There is no one he can confide in about how he feels. Timmy while mature for his age was still too young to understand these things and the only friends he had all lived at Nonnatus House.
Not for the first, he was alone with none to share how he feels.