SOLVED. Medieval England arranged marriage, husband wanted to be a Monk, he's sent overseas, she is pregnant and has gift to heal, he disappears, she searches for him, baby born on the road-named Peregrine. Spoilers ahead.

[Mersadis]

SOLVED: In Pursuit of the Green Lion, #2 in the Margaret Ashbury novels

A widowed mother of 2 daughters is married to the 2nd son of a Baron who wants to become a Monk instead and write (he has permanently ink-stained hands). They agree in private to keep their distance but as they get to know each other, they fall in love. She gets pregnant and he is sent overseas about the same time (I'm certain it is Crusade related).
Before she got pregnant, she healed a horse's broken leg in a river/creek with her gift. The Baron sees but does not say anything until he falls ill. She has to tell him she is pregnant because her gift focuses on the growing baby during pregnancy.
The husband goes missing while overseas and the heroine leaves in search of him (while pregnant).
I don't remember anything in between here.
Heroine gives birth in the woods while traveling and husband names him Peregrine after a Saint (also meaning "traveler").
Final scene in the book is of them laying in bed. He goes into a meditative state where he can literally hear everything, including the Earth "breathing".

I read this about 2005 and it was old then. It had a light green cover with a detailed pattern on front similar to celtic knots and the "bejeweled" covers from the 90's. I found it in the the fiction section of the library, not the romance.