I haven’t posted much for a while. I felt my situation differed enough, and possibly triggered some, that I wasn’t sure I belonged here. That being said, because of recent events, I felt compelled to comment on this topic. SI has lots of posts on it, and I’ve discussed it with friends over the years (male and female). Due to the public nature of my D-Day in my fairly large community and some unique aspects of the follow up, some BS’s I didn’t know were BS’s reached out, and this topic came up then, too.
When someone asks advice on this, I find it’s hard for that advice to reach them. They think every "size doesn’t matter" comment is just placating them, and don’t accept it. This view is hardcoded in them, and infidelity makes the situation much worse. That’s finally what pushed me to post. I wanted to take a crack at it, and relate some of arguments around it. I won’t be so arrogant to say all this is right, so please take it for what it’s worth.
1) Don’t be embarrassed to be embarrassed. This is a subtle, but important point. Many BS’s feel awkward admitting this insecurity. They are embarrassed at being embarrassed, and some have felt a "what’s wrong with you" vibe for focusing on this. Maybe I see it because I’m male, but I think media is full of big penis vibes. Movies, and songs drop comments about it and many sex jokes push this message. One of my female friends pointed out that’s probably because the people creating a lot of that are men pushing that image, so self-fulfilling, which is a great point. Still though, it is the world many grew up in hearing this and solidifying that view, so there’s no shame in having that view.
2) Think about what bigger really means mechanically to you. Sarcastically, if you think bigger is better, then much tighter must be better for you, right? If that’s the case, then when you masturbate is your goal to squeeze as tightly as possible, to the point of almost pain? Maybe that’s the case for some, but I’ll bet not. Turn this around and imagine this from your partner’s point of view of that discomfort internally.
To say this very crudely, imagine that sex wasn’t about how much a space is filled, but rather how the nerves, and sensations are built up around that interaction. I think this is the source of expressions like it’s not the size of the pen, but how you write.
3) What does bigger really mean to your partner. I’m going to overstep my bounds further with more generalizations here. A large majority of female partners need clitoral, or non-penetrative stimulation to climax. Large penises can result in the opposite. Regardless of how the vagina may adjust to accommodate, when it comes to causing discomfort, hitting the cervix, and missing more sensitive spots like the clitoris, or "g-spot" can result in a very different experience than a partner thinks is happening (a view likely driven by porn, which is so far from reality, I'm not going to address it further).
Some of my female friends have commented on the pain associated with a much larger penis and how it can be more of a challenge than a pleasurable experience. I have a couple of good-hearted male friends that are well-endowed and you should hear them talk about concerns with hurting their partners, and the effort it takes for the partner to get used to their lovemaking. In the context of society’s stereotypes about penis size, it’s a terribly ironic situation to be in and can make them nervous about first time sex with someone, especially if they care for them.
4) You don’t know penis size when picking an AP. Expect in rare instances of dick pic exchange (if authentic), most APs seem to be a result of convenience and availability. To go further, according to some studies, it’s often insecure males seeking affairs for affirmation, so it may actually be an opposite situation.
5) Read about anatomy. In light of infidelity, perhaps researching this topic could cause more triggers, but, if you’re focused on penis size, researching the related anatomy and preferences could help. The highlight that surprised me was that the clitoris is not just that one spot. It’s the entire range of nerves encompassing the vagina, outer portion, and other parts, with only a portion breaking the surface. There is so much more to all this than size, and understanding this could help you immensely in current or future relationships, which can help self-esteem. Regardless of how things ended with my XWW, taking the time to understand her mechanics was one of the best steps I took in my relationship, and I’ve applied it to new relationships.
6) Everyone is different. I have had somewhat unusual circumstances that led me to a range of partners. There’s huge variation in what works for people. Ironically, many of my female friends didn’t realize the extent of this. They thought what worked for them usually worked for others. If you really take the time to work with someone on what works for them, you may be surprised. They may, too, and discovering something like that together can be an amazing bonding experience.
7) What if it really does matter. Okay, last bullet point. There are "size queens" out there. They seem to be rare, so immediately assuming someone is one (and that it is why they sought out the AP) is a mistake, and likely a conclusion driven by ego. However, some do exist. My recommendation in this situation is not to judge yourself, but rather own the dynamic. See it simply as a quirk with their body, put your ego aside, and explore the use of toys with them. I realize that sentence is a big ask if your ego is wrapped up in your penis (as mine was for years), but, if you can accept that this goes beyond that, you can have love making well beyond your penis and your partner will be very appreciative. Surprising advantages are that the use of toys will remove pressure to maintain an erection for them to climax. Depending on your partner, that can be amazingly freeing. And, I can say without any doubt that a silicon-based device will stay erect longer than any flesh-based erection ever could 
.
