According to JW teaching, death is the end of marriage. If one spouse dies, their marriage is "legally" ended. If, say, the wife remarried and survived into the paradise with her new husband, they would have to remain married unless death or adultery occurs. The resurrected spouse would not have the "right" to be with her, so technically, yes, he would have to pretend to be happy with this.
Right now, there is an ongoing debate among Jehovah's Witnesses whether resurrected people would be able to marry, or remarry, in the paradise. As FreeGirl2006 said, it is possible the resurrected spouse would not be able to marry. However, the contrary is also possible as Jehovah's Witnesses have not yet decided. They are not yet sure as to what one verse, I believe from Matthew, means. In this verse, Jesus speaks of the earthly paradise, heaven, and marriage. Therefore, they don't know whether the rule against being married after Armageddon is in regards to the earthly paradise or heaven.
I had this exactly same conversation with the elders from my area some time ago. All I said above is true for the Jehovah's Witnesses in my city. I'm not sure whether they would have other interpretations in other countries. I live in ON, Canada.