Polyamory
Polyamory is the practice and acceptance of intimate relationships that are not exclusive. There are many variations of how couples agree to such arrangements. Some couples choose to practice polyamory instead of monogamy.
Are both of you interested in being in a polyamorous relationship? Having similar ideas and feelings about this can make a big difference in how well this kind of relationship will work for you.
Although it makes sense to discuss polyamory as you enter into and develop your relationship, some couples raise this subject having been in a monogamous relationship for some time. The most challenging situation to work out is pursuing discussions of polyamory after one partner has had an extramarital affair.