You can start by forgiving your partner for insisting that you change your political views. This will not suffice to quell the conflict. Once you forgive, and your exasperation lessens, try to have a heart-to-heart talk. Be honest, and gentle, as you communicate your frustration with his insistence. Try to reach reconciliation by talking out specific ways in which both of you can respect each other as persons even with political differences. It will take time and effort, but may work.
For additional information, see Forgiveness for Couples.