1- Remember life is a trial, and this is your trial. When we are in out comfort zone, it’s easy for us to pray. But when we are around someone who doesn’t, it becomes more difficult. Simply realizing this is one of your life trials helps, and it gives you greater commitment.
2- Be open with him and tell him. Tell him that your spirituality has been affected. Don’t put the blame on him because he might get defensive. Rather consult him. Ask him what he recommends. Doing so might motivate him to be consistent with his prayers and even encourage you to pray.
3- Be more familiar with the significance of prayer and its effects. Such reminders are really helpful. For example, I recommend seeing this series:
4- Plan your prayer in advance. Have a daily planner that tracks your schedule, and schedule your prayer in advance. It makes one more committed to it.