The first reason Paul gives for the singles in the church not to marry is that because of the distressing situation at that time, being married would only increase the stress and difficulty of life. It could be that the 'present distress' Paul is talking about is the Roman's persecution of Christians at that time. A single person would not have a spouse and children to protect in such times or even to be a temptation to compromise thier faith.

Matthew Henry comments on this verse thus...

This is good, says he, for the present distress. Christians, at the first planting of their religion, were grievously persecuted. Their enemies were very bitter against them, and treated them very cruelly. They were continually liable to be tossed and hurried by persecution. This being the then state of things, he did not think it so advisable for Christians that were single to change conditions. The married state would bring more care and cumber along with it (v. 33-34), and would therefore make persecution more terrible, and render them less able to bear it. Note, Christians, in regulating their conduct, should not barely consider what is lawful in itself, but what may be expedient for them.

(from Matthew Henry's Commentary)