When you are in a serious relationship / marriage it is normal to be invited to accompany your significant other to events at their jobs. You should expect to be invited to company holiday parties, company games, and family days. If you were originally invited to such events but no longer receive these invitations something may be amiss. Your cheating partner may be interested in spending more time with the person they are cheating with at work. They may just not want to spend any more time with you than what they have to in order to maintain the relationship.