How to stop assuming every chick has a “better ex”?

Every time I meet a chick, (ESPECIALLY if she hot) I just assume she’s dated guys with massive dicks (or at least thick ones) and that she’s specifically “into” being “stretched out” (Almost all women are)

(Something I cannot provide as mine is long and skinny)

Also doesn’t help that a LOT of women have said that “pencil dicks are the worst” and “girth matters most” (something I’ve heard online, and IRL from friends)

How do I stop this?

I’ve heard the whole “just convince yourself it doesn’t matter, and the emotions and love and all that is more important”

But I just can’t get myself to believe that

Yeah love might make her stay, but that doesn’t mean I’m the “best sex” (physically speaking) she’s ever had, it just means my personality is good enough that the fact my sex is “mid” is acceptable (at least it’s not “bad” right?)

But I don’t want to be seen as “mid”

As the “guy you marry”

I’d rather be the guy, who she has AMAZING sex with, and she’ll never forget about me, and even when she’s in a happy relationship with some new guy, when her friends get her drunk and ask her who her “best lay was” She’ll say me, not whatever guy she’s currently with

But everyone is so willing to give up and just be the “mid boyfriend”

Here’s an example:

I had a female friend, let’s call her K

K was known for fucking a LOT of guys, whenever she wanted, she cheated on every guy she’d ever been with, it was VERY easy to have sex with her, all you had to do was walk up with confidence and she’d get butterflies in her stomach, and she’d act on that feeling IMMEDIATELY, every time

She constantly bragged about the guys who had MASSIVE dicks, and said multiple times she preferred them, and even told a story of a male friend who tried to fuck but when he pulled his dick out it was “the size of her pinky” so she just laughed at him and said “what am I supposed to do with that?” So he just brought her back home and dropped her off

K ended up dating my friend (who multiple chicks had already said he had a very small dick) And she said it was small, but he “knew how to use it” and was obsessed with him for like a week, until he cheated with his ex

Then she starts saying “idk why I settled for his tiny ass dick, just because I LIKED him, nah fuck that I’m going back to big dicks that I ACTUALLY like”

She also tried to fuck me and cried in my arms about why I wouldn’t one night (even longer story)

I just didn’t want to be “settled” for, knowing there was probably some guy who “hit her in spots that other guys can’t even reach” (In her exact words)

Like, she praised massive cocks SOO much, that like clearly that’s the only thing she likes

And now I automatically assume every chick I meet is just like K

And even if she turns out to not be a “slut” I still assume her ex was better than me

It’s just hard to walk around with ANY confidence at all, when I know my penis is skinny and almost every girl feels “loose” to me

I’ll never be able to “fill” a chick, so I’ll never be “the best” just “pretty damn good”

So what’s the point in even participating at all?

Might as well just masturbate alone instead (and pretend I AM capable of “filling” a chick)