All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Abandoning prayer is a grave major sin whether during the honeymoon or at any other time because this is a terrible crime and a great sin. It was authentically narrated that the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, said: "What stands between man and disbelief is abandoning prayer." [Muslim, At-Tirmithi, Abu Daawood and others]
The believer should always be in contact with Allaah. If Allaah bestows upon him the favor of marriage, his worship and obedience to Allaah should increase in gratitude for this blessing. It is impermissible to abandon prayer even at times of engaging in Jihaad against the enemy. Allaah The Exalted Says (what means): {And when you are among them and lead them in prayer, let a group of them stand [in prayer] with you and let them carry their arms. And when they have prostrated, let them be [in position] behind you and have the other group come forward which has not [yet] prayed and let them pray with you, taking precaution and carrying their arms. Those who disbelieve wish that you would neglect your weapons and your baggage so they could come down upon you in one [single] attack.} [Quran 4:102]
Know that whoever abandons prayer should be killed according to the view of the majority of scholars and they divided into two opinions concerning his disbelief. So, how could a rational person lead himself to such a destiny?
Allaah Knows best.