If it were easier, it would just be easier and you wouldn't be distraught at all or need to do any of the mental gymnastics. You just admitted it yourself, too - it'd just be pretending. So if it's going to hurt either way, why bother with the extra stress of it to make it worse? You're only punishing yourself doing that.

You aren't losing it. Even if you change the past that much, it will still have existed here and now. And you haven't lost it already, either, because I sincerely doubt he'd give up on you so easily.