You make it out like there's no reason a dude would ever have a desire to wear a dick sleeve, when in reality I'm sure some don't, but some love to see how crazy they can drive their partner with it. Some people experience physical sexual pleasure from giving their partner pleasure, hence the amount of thrashing and moaning going on in mainstream porn. A dick sleeve is a way to amp that up, for both parties' mutual benefit. Sure, with a tactless or self-absorbed partner it's use could lead to terrible insecurity, but so could most things.

Perhaps this is TMI for a public forum, but I do feel no small measure of discomfort and inadequacy about not being able to have fully penetrative sex as a woman. It's not something society tells me I should be able to do, it's something that my own BRAIN tells me I should be able to, and when it comes to relationships I don't think the source of the feeling should matter if we're talking about importance.

So if we compare these two circumstances, I think they're quite similar:

I want to fuck him a certain way, he wants to be fucked a certain way, but there's something (penis size for you/lack of penis for me) getting in the way. So instead of saying OH WELL doing this thing that we both really want to do might stir up some feelings of inadequacy so let's just never do it, we do it with full knowledge that we're both going to enjoy it a lot, and also sometimes one person might feel insecure and the other will comfort them about it. Then the insecurity will fade, and we will carry on with our otherwise happy lives.

You can't ever completely get rid of self-consciousness forever. You just need to find a partner who is considerate of your feelings (aka will make a serious effort to phrase necessary things in a way that won't hurt you), and will work with and do their best to make you feel better.

you can argue that I might make her insecure about not being right for me, not being a homosexual man.

What I'm saying is that if you have a close, solid relationship, this is not something one would need to worry about. Even though my bisexual husband enjoys having sex with men and openly acknowledges real penis is better than the rubber penis that is the best I can give him, I'm not insecure about him leaving me for someone with a penis because of all of the other reasons we like and care for each other.