Men usually go to smaller, poorly-furnished apartments. They miss the routine and they miss the children. They lose their friendships, because those were managed by the wife. When the kids come to visit, the man often does not know quite what to do with them. Older kids have to miss being with their friends to see their father, and this resentment is layered in with whatever feelings the children may be having toward their father.
Loneliness leads to bitterness.
Typical reactions are to suppress the emotions, and channel the loneliness into bitterness and anger. You should try not to let this happen. Loneliness leads to remarriage. Another typical reaction is to find another woman quickly. Many men remarry within one year of the divorce.