Are priest allowed to have sex ?
In real life, no. Catholic priests cannot marry and have children (which involves sex) after they have been ordained. However, there have been multiple cases in history where some priests have sexually assaulted minors and women. Because you know "it's not illegal if you don't get caught". There are also cases where a married man can be a priest but only if they are widowed or divorced but not all churches accept that.
Although in recent news (you can fact check this because I'm not too sure) priests or catholics from places other than the Vatican are trying to remove the celibacy requirement, and apparently, new priests are open to this idea so that they can get married and still be a priest.
We will all go to hell. ヾ(❀╹◡╹)ノ~