I think pastors should already be married by the time they are in leadership since letter to timothy states they are to lead their own household/family before they lead the church family.
I think its weird to have a really young pastor who doesnt have his own family and is dating, or conversely a really old single pastor who has ditched his first wife for someone much younger. if he was widowed it might be fine though especially if the first wife was ok with him remarrying after she died. I have heard of some situations like that.