Is there any advantage in forgiving and reconciling compared with forgiving and not reconciling? If I forgive but do not reconcile, will this weaken my ability to forgive in the future?
There is no general rule regarding forgiving and not reconciling. In other words, your not reconciling with someone who is not remorseful or who is unrepentant (when acting very unjustly against you) should not weaken your ability to forgive in the future. In contrast, if you refuse to reconcile with someone who in fact has remorse, has repented and, where possible, has given recompense, then you need to examine your own inner world. Perhaps you have excessive mistrust or resentment and these can get in the way of future forgiving.
Whenever I try to reconcile with my partner, I am reminded of the mean things that he did. It kind of sets back the reconciliation process. What do you recommend?
This is not uncommon. When the old feelings emerge as you try to reconcile, I recommend that you once again start the forgiveness process with this person and with a focus on the particular hurtful event. The more you go back to forgiving, the deeper the forgiveness tends to develop in you.