This is just a thought....but, as a woman, if I was worried or convinced that my husband might cheat, the LAST thing I would ask him to do is get fixed. Because to me that would be like saying "ok, go have sex with someone else now since you can't get them pregnant!" It would help reduce the chances of getting caught. (keep in mind that I may have a screwed-up way of thinking!) Or could it be possible that she's afraid you may start another family with this "other woman" that she's afraid you'll find & love them more & leave her? I have depressive episodes too & this is how my mind works, but of course, I can't speak for your wife. She may not think the way I do. Best of luck to you!