Just discovered this game and wanted to say it looks great so far! I disagree with the people who said you've shown too much at the start - the sharing scene on the beach proved to me you know what you're doing and have a clear idea of where you want the game to go, which makes me more interested in investing time into playing it. Also, just ignore everyone arguing over the tiny, perfect details of definitions. It's good to represent the game correctly, but what exactly this or that category involves in every exact circumstance is a rabbit hole it's not worth your time to go down - and there will always be someone here wanting to start a fight over the most unimportant things. Just ignore it and focus on the game, not the "fans" who just want to nitpick.
I do agree with the people who are less happy with a small-dicked MC, partly because these are games we fantasize ourselves into, and we'd all like larger dicks. He doesn't need to be gigantic or the character with the biggest size, he could just be not obviously small. The other reason I'd argue for it is story-based: it's refreshing to see a confident, well-endowered husband sharing his wife rather than the game cliche of a husband with a small dick letting his wife have the larger cocks she wants. Especially if the plan is to have choices where the husband can have sex with other women also, why not avoid the cliche and just give him a decent sized cock?
But at the end of the day this is your game and you need to make choices that you're happy with. I really like the art, the dialogue, the relationships you're setting up in the game. Having both the close friends for intimate sharing/swinging AND having the sister who may open the door for more transactional sex through porn shoots down the road is a brilliant setup and a great way, in my opinion, of being able to have distinct "chapters" to the journey the husband and wife go on, if you want to do it that way, where the two of them get more and more comfortable and also expand their options for partners and, perhaps, "supplemental income" since farming is not usually a lucrative job...
You've got a great start here - keep it going! I'll be excited to see what you have planned!