Well, there are several good strategies for battling Liches. Perhaps the easiest is using a scroll of Protection from Undead, you can buy those at most temples. If you use one of those, the Lich doesn't even notice you while you pound away at him. Just send in one of your fighters and kill him while he just stands there wondering what's happening.
Otherwise, you'll have to rely heavily on magic. Cast all defensive spells you have before going into his tomb, and once inside, dispel his own protective spells with Breach and the like.
And about Anomen, I don't think he's as bad as you hear some people say. He's good at what he does, only a little arrogant. But this is coming from a guy who only plays male characters, so Anomen isn't the only choice I have for romance in the game.
