Dean Roberts was speaking after more than half of the Church in Wales Governing Body voted in favour of same sex unions.
Sixty-one out of 120 members of the body, which is made up of bishops, clergy, and laity, had a three-hour discussion about the topic yesterday before holding a secret ballot.
Fifty voted against allowing same-sex marriage, while 9 voted in favour of blessing gay partners in civil unions but not allowing full marriage.
A two-thirds majority is required for Church in Wales bishops to consider drafting a bill to change to the Church's constitution. In this event, the bill would then go back to the governing body, who would again require a two-thirds majority to pass the bill and thus change the constitution.
The Archbishop of Wales Revd Dr Barry Morgan (pictured below) told the BBC it would be "foolish" to bring in gay marriage at the current time, because it could "rip the church apart."
Dr Barry Morgan retired as Bishop of Llandaff and Archbishop of Wales earlier this year
The meeting in Lampeter, which has been scheduled for some time, came after the Archbishop of Canterbury Most Revd Justin Welby announced he'd asked the 37 other primates of the Anglican Communion to meet in January to discuss the issue of same-sex marriage, as well as other issues.
The US Episcopal Church has already voted to recognise and allow same-sex marriages, while other African and Asian branches of the Anglican Communion are strongly opposed to them.
Dean Roberts spoke and voted at the meeting in Lampeter, and told Premier: "I was really glad that the debate went well and people were very considerate towards each other despite very stark disagreements.
"If it did pass there's a sizeable amount of people who are against changing what the Church believes about marriage, and so it could indeed split the Church [in Wales].
"Of course we do have other Anglican groups now in the UK forming churches, and so it could be disastrous for the Anglican Communion.
"The Bible and actually the weight of 2000 years of church history, certainly on this issue, should speak first."
Listen to Premier's Aaron James speaking to Dean Roberts here:
