He has been speaking to the unmarried (1Co 7:8) and to married parties, both of whom were Christians (1Co 7:10). By the rest he means married couples, one of which remained a heathen.
I, not the Lord
These cases are not included in Christ's declarations.
Be pleased (συνευδοκεῖ)
Rev., be content. Better, consent. Both the other renderings fail to express the agreement indicated by σύν together.