a guy asks me to join a tour on July 4th

A guy I knew from a seminar asked me to join him and three others for a tour on July 4th. I told him I am not sure whether I will go because I have some work to do. The real reason is that I married and really feel guilty to go out with other guys without my husband around. I feel it is not fair for him.
Since I got married years ago, my world is getting narrowed gradually. Today it merely consists of my job, study and my faraway husband. I know that a lot of couples will not choose to stay apart while still in marriage. I try very hard to convince my husband and me that this is the right thing to do, and pray to Lord everyday that "please bring the gifts he prepared for us sooner".  Life is tough. On the way to success, there are so much sacrifices. We have to give up so much to get those that not every one is capable of or willing to get. Mom always tell me that when I climb to the top of the tree, the peach are mature and ready. I believe in her.