Commitment Schmittment

When I was wholeheartedly committed in my longterm 8 year relationship (though not married mind you), I didn't ever question the committment, it was so effortless.

Now that I am (1) out of a relationship, and (2) interested in someone who's engaged, commitment seems very strange - like, what's all that about? How can he be sure? How solid is a committed relationship?

The ridiculous things the brain does. It is like i've taken a love drug - to quell maturity and rationality.