a jazzy love song in worship?

The other noteworthy thing from worship on Sunday: Nashville's Michael O'Brien singing "This is the story" and a jazzy love song called "Something about us". The former fit the sermon perfectly. The latter could be taken as purely secular, but was attached to worship by saying that the "something" was Jesus-- and it was attached to the service through the communion meditation and the analogy of the believers' marriage to Christ.

On the latter, my first reaction was "nice song", etc. My second reaction was to be ill-at-ease to hear "that sort of music" in church. My third reaction was to ask why I was uncomfortable. Is it ok to hear a "love song" in church on any given week-- or should that be reserved for a marriage-oriented message? In the end, I decided that it was all-too-rare but good thing to celebrate marriage in church. Where else?