Mutual affection between loving partners is not considered sinful by most Christian denominations.
It does mean, however, that we should be careful about what is in our hearts and to make sure we maintain self-control when kissing.
All these vile things come from within; they are what defile you" (Mark -23, NLT). If the answer to any of these questions is "yes," then such kissing may have become sinful for you.
Is the kiss making you want to do more with that person? This doesn't mean that we should regard all kisses with a dating partner or with someone we love as sinful.
Wait a minute, maybe we aren’t so different after all! Everyone has the ability to relate to the fervent wholeness of faith, and to understand how it can permeate every aspect of one’s life.