Is a cheating husband still a Catholic?

Like any family, the Catholic Church is composed of people who make mistakes, both great and small; however, a person remains part of the family of the Catholic Church unless he/she leaves by a formal act such as joining another denomination or religion. This applies to a spouse who is committing adultery. The teaching of the Church on adultery is that it is a sin, which when confessed, is forgiven. The action on the part of the offended spouse, as hard as it may be, is reconciliation.