Talk to your partner early and often, if you have the opportunity -- as with all things in relationships, good communication makes everything better. If your partner knows your underwear preferences from early on, it's just who you are, and acceptance will be much more achievable. If it is actually a dealbreaker for them, you can break up and move on.
This is more difficult if you've been in a relationship for a while. Others will be able to speak to that experience better than I can, however, as before, communication is essential. It's probably best to take things at a slower pace if your partner is not immediately accepting. If you're longing for floral lace lingerie, maybe wait on that and stick to basic briefs in black or white for a while.
It's worth remembering that this is likely to be something much newer to your partner than to you. While you may experience this as something you've been thinking about for a while and are now very certain of, they may experience it as new, sudden, and uncertain. I don't want to belabor this, but keep communicating -- even if it's uncomfortable sometimes -- perhaps especially when it's uncomfortable.
Definitely state how much better they feel than guy's underwear. I recommend not using the ol' "they're comfortable" reply but state how you like the feel of them much more. How they feel when your member moves or when you move.
If you are sexually active with the person, I bet once they get a chance to feel you with them on, they will agree that you should wear them.
(on a side note though, there are some women who refuse to accept their SO or husband wearing panties as they have a fear of you being too feminine, or possibly gay, and no amount of explaining will convince them.)
I think, before even bringing up the subject of underwear, you'd want to find out if the person you're dating/meeting is (or isn't) an independent thinker. By 'independent thinker' I mean a person who blazes their own trail versus one who simply 'follows the crowd', meaning one who lets 'social norms' do their thinking for them. I have found over the years that panty wearing guys and their partners tend to be independent thinkers.
This subject can usually be broached when your partner might make a comment about something a 3rd person is wearing. This 'third person' can be a chance encounter with someone on TV, someone in a public place and so on. Be ready, independent thinkers can sometimes be found where you'd least expect them.
An example of that is a woman I recently met. She is a member of my church and also what I'd regard as an intensely religious person. Anyway, while siting together and talking at a church picnic, I bent down to pick up something she had dropped on the ground. My shirt pulled up and then she noticed the waist band of my panties. She said: "Oh what pretty panties you're wearing. I wish my husband would wear something like that. Your wife is very lucky to have you." That woman would have been a 'keeper', had we both been single and 'eligible'. As I said before, be ready because opportunity can be found anywhere.
__________________
No one ever achieves notoriety by conforming to so-called social norms. With that in mind, just step into your big girl panties and let life happen.
I have always found that best way to introduce the topic to a partner is to express an interest in wearing her panties specifically, not feminine attire generally. After being intimate, say you want to wear her panties to be reminded of her. It's true, after all. I have never known a lady not to be flattered by this.
This usually evolves in two directions: she'll either offer more of her thing to you, or if she's really attached to her items or they don't fit you, she'll buy some of your own for you. Matching sets tell you when you've got it made.
