Is it in Rig Veda that a Hindu could marry a second time even if he had a wife

Thanks for the query, Praveen. The Rig Veda is not the only source of Hindu law. Customs are also a valid source. To legalize a custom as valid, there are some conditions but as a result, ancient Hindu law had many repressive customs that were adopted as unspoken laws. As many customs became dominant and unmonitored by any religious body, social evils of today became valid customs in ancient Hindu law. Out-of-the box religious leaders such as Swami Vivekananda questioned the validity and relevance of customs such as practising untouchability and casteism, prevalence of child marriage, ban on widow remarriage and adoption of sati as a noble custom. These are some examples of validated ancient Hindu law customs. Another example is that of a Hindu man being able to have more than one wife while the first wife is alive.