Two things jump out at me. 1) You were upset about your weight and they were making a "joke " of that, and 2) you explained your thoughts and Sward "sighed heavily" and asked you to stop worrying.
I know for me, my feelings and thoughts are worthy of consideration, and it is good to have them validated, instead of teased over or made light of. Sometimes I am ok with that, and other times, I can get offended. It is important to me for the people in my life to be sensitive to my moods.
Did either of them apologize for teasing you about your weight? Did they take a look and realize where what they said may have been hurtful, even if not intentionally so? Sometimes a simple acknowledgement and an apology can make a HUGE difference to me.
Weight is a big deal to women -- we are bombarded by images and standards of beauty that are impossible to achieve. Rather than teasing you about that, it would be nice for the men who love you to focus on saying some endearing things about your beauty, both inside and outside, wouldn't it?
Your tendency to worry about how things are working, in this unconventional life of a V, where there are not many models to follow, well, I think that is NORMAL. Your sensitivity and ability to feel and love deeply, that is probably part of what brought you to polyamory. I think your men love that about you. It's good you defended yourself a bit and hopefully they will both be a little more sensitive, themselves, in the future.
All women get soft bellies over time. It's part of our biology, and it is OKAY. Phy, I am sure your inner beauty and the sparkling light of love in your eyes far surpasses any of that outside stuff anyway.