John Gottman has some good ones that have great activities and reflection to do! I really recommend The Seven Principles for Making marriage Work. And Baby makes three is good too!
Also relate do various books x
Things no one taught us about love - vex king. Not specific for marriage but a very good overall breakdown of attachment and how we experience/ show love & where the disconnects are. There are some questions and things to do with a partner and advice in there xx
Baby Bomb.. I have not read it but was suggested by my perinatal mental health provider.. wishing you both well!