us census data shows that slightly under 50% of marriages end in divorce so you're right the odds aren't too good but 60% is a pretty big exagerration. i just think it's worth a chance if it's someone you really love and want to get married to and have given it enough time to get to know each other really well. when do you know you're really ready and this person is really the one? i guess you don't until after the fact but that's why you take chances in life....Carpe Diem!!
lots of interesting stuff here:
http://www.census.gov/prod/2002pubs/p70-80.pdf