Ditto on the "this is just one person's opinion," and "whatever you do, do it for you" caveats of the other responses.
But - there is a relationship issue here, and not just a weight issue. You say you just moved to the other end of the country to move in with your partner. And he just raised this issue of your weight. So it seems to me that there are some questions the two of you need to be talking about - like, is he feeling pressured in the relationship, and is responding by pushing you away? How does it change your relationship to be living together? What did you give up in moving, and what were your expectations? These are "we" issues, and won't be solved by you working on the "me" issues of your health. Not that those aren't important and good to be working on, and increasing your self-confidence should also help your relationships - but not necessarily this one, if you don't also address the "we" issues.
If you need help in how to talk about "we" issues, and building love and trust, I recommend the books by John M. Gottman - "The Seven Principles for Making Marriage Work" applies to all committed relationships, not just marriage. I have used it in premarital counseling (I am an Episcopal priest) and in my own relationship.
Sorry to depart from the weight subject - I'm not selling anything, so I hope this post is consistent with the rules. Best wishes -