I don't tend to post or comment anywhere since I'm a bit of a lurker, but my thoughts echo the earlier reply from asdfjkl;. Disclaimer, I'm also very straightforward, so here goes 😅
Any decision involving how you look, feel, or behave should be 100% your own. Anyone who loves you will respect that, fetish or no fetish. If you were not attractive enough for him before you gained, then a lot of questions may need to be asked. You may also need to ask yourself if your relationship might have started due to your "potential" to gain. I would hope that is not the case, but it is something you may need to ponder. I'm not necessarily suggesting ending a relationship, but some hard boundaries between you and him might need to be set. From what you have stated, the respect and attraction are lacking right now in your relationship. If that respect is not being shown, you need to have a serious conversation and possibly a contingency plan. I really do hope it all works out, but make sure you prioritize your mental and emotional health...no matter the other consequences because love includes loving oneself.
Now, back to lurking 😎