My feeling, and I believe that the consensus here, is that a strong, emotional relationship/marriage and nonmonogamy, i.e. sex with others (even if it includes some emotion) are not incompatible.
My now wife and I went the monogamous route after we fell in love before we were married and afterwards for a couple of years, but then eased into playing with others, first her then both of us. As many here have also experienced, it actually made our love and marriage stronger. Talk about it, everything you both are curious about, what you and she enjoyed and did not, then move forward on your adventure, which doesn't have to be symmetric. In our case my wife started first by renewing sexual relationships with ex-boyfriends. After a while she really wanted me involved, first having MFMs with them and later moving to couples swaps.
With the right person, it is work, it is fun, it is exciting, it is satisfying.