You're not providing any details aside from the fact that you might just be a wimp. If the axle nuts you're using aren't the good kind that have a rotating washer attached or the serrations facing the dropout are worn, that may be your problem. If your dropouts are aluminum and have stainless steel inserts, that may also contribute to the problem.

If my 115 lb wife can tighten her axle nuts without her wheel slipping forward, so can you.

/unclerico