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.
__________________
Pretty panties and bra put me in my happy place and are made to be seen, not hidden.
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.
Honesty is best! For me growing up mens lingerie was popular but was expensive. I liked how it made me look and feel. Then I tried woman's lingerie, it was much more affordable and readily available. Since I liked the fit and feel of panties and was a big boy I have been buying them. Some days my panties are practical and other days they are also pretty, yes it is odd but I am just me. Even if it is a fetish only, better to be honest than to be discovered. Good luck
When I started dating again I wore my panties with a t-shirt when I was spending the night at my girlfriend’s. They were plain silky navy blue bikinis and she thought they were men’s undies and she loved them. She was like wow those are so sexy and she said all men should wear them. Later in our relationship she said if we broke up she would never want to see a man in tighty whiteys ever again. Eventually I was wearing all kinds of lingerie around her, not just panties…. Stockings, garter belt, nighties and we even switch and wear each others panties. So much fun.
__________________
You know what you MUST wear and what feels so wonderfully good.
I get great satisfaction wearing feminine panties.
Maybe I was just lucky or something but it was practically my wife’s idea when we first started dating. We were lying together naked one morning and she commented on my butt. I jokingly asked her to find something she wanted to see it in and she brought back a few pairs of panties. I tried to hide my excitement and told her the black and pink striped bikini I first tried were actually kinda comfortable. She wanted me to wear them all day and said she wanted me to keep them and it just evolved from there.