Short answer is that Christianity doesn't give a one size fits all solution to issues like infidelity. Personally, I think it depends on the underlying issues. In the new testament verses regarding infidelity and divorce, many people forget the context. Jesus was speaking to a group of people who had bought into a 'divorce for any reason' mentality that had become pervasive at the time. Taking his words in context with the old testament, I believe he was telling them that burning dinner is not a reason for divorce. It has to be a breakdown in the covenant, like infidelity. But he didn't say you have to divorce.
I was trained in a problem-solver role within a business unit of my company. We were taught to answer similar questions with two words: it depends.
They give lip service against the practice but are quick to give excuses for the most outrageous transgression. They forgive quickly and move on. No atonement seems to be necessary no sympathy for the betrayed spouse.
The cheater is welcomed back into the fold like the prodigal son. Seems there is a panache associated with male cheating Christian fundamentalist, they garner great sympathy and a wealth of fellow christians to pray for their souls.
I think the faithful spouse should cheat too if for nothing else than to get all of the support that the wayward spouse gets and some of the fun of sex with a new partner.
Christians, at least of my faith, are against it 100%...I think Catherine602 is a little off in her observations, unless she belongs to or learned about some cult religion or something. Yeah we believe in forgiveness, but we also believe that God would not choose for you to be in a faithless marriage. I think that ones thoughts on infidelity is more of a human morals questions than religion though. I mean you don't have to believe in God to understand that it is morally wrong for you to cheat on your spouse, unless you are in an open marriage or something, which is a couple's choice.