I could say give Jareth a pass on this one.... it would make sense and could be his way of protecting her from either some sort of damage or the knowledge of what he went through.... however, there has been so much good and moving forward between them!! A mind wipe could potentially remove all that progress from her side (while Jareth suffers knowing what he lost) also Sarah would be super pissed if she ever found out. -_-;

Sarah knows what Jareth is capable of and still wants to trust him. In #251 (right before the collapse) she told him she knows and still hopes that he won't go all villain on her. Sure that doesn't really count wiping her mind to help her in some considerations of the matter but, the fact would still be that he manipulated her mind and erased her memories. Not something Sarah would accept sitting down. She is a fighter and I feel she would rather know the truth and work through it rather than believe a lie and have the truth hidden from her.

Sarah would find out one way or another. Most likely through Erik by accident or something.
While I believe Jareth knows all this, he would realize what it means to both Sarah and himself, he very likely would choose to sacrifice himself if it meant protecting her from anything. 

So as my inner fan-girl yells "JARETH NO." since I am on his side and want things to go well for him (it's super cute when he is happy or annoying Sarah... usually) I also say that if Jareth does a mind-wipe.... well, I've gotta give him a pass but, I hope he doesn't go down that road. And of course OMNOMNOMDRAMA!