The fact that he’s acted distant toward you is a problem. I don’t get why so many people act like a partner gaining weight is a personal affront. It’s certainly not the most pleasant of things, but come on – it’s often an indicator of other stress and priorities coming into a person’s life, even depression.
He does deserve props for not pressuring you or issuing ultimatums or calling you names (which, unfortunately, is another common tactic along these lines).
There is no excuse for acting distant, however – that’s just another passive-aggressive form of punishment against you, only you had no idea what he was upset about until you asked. Were you supposed to read his mind?
His suggestions that you guys eat healthier and work out together are noble. But does he really intend to follow through with that, or is it just code for, “YOU need to work out and eat healthier?” That’s another common tactic I see, sadly. He’ll be eating beef burritos and kicking back shots while he hands you a salad.
I think a frank discussion is in order. A simple, “You’ve been acting distant towards me lately, and it upsets me that rather than being honest with me so that we can solve this, you would become distant from me. I didn’t gain weight to insult you or to hurt you. I would like to work on my weight, and I need you to be supportive with that.” Then, outline the behaviors you’d like for him to display – i.e., maybe you both go biking together, I don’t know.
Your body is going to grow and evolve over time – but there is a difference between gaining weight in a pregnancy and gaining weight as a result of excess caloric intake, which I think is the difference in perception for many people. He may well be one of the few who finds a pregnant body unattractive, or he may resort to jerk tactics after you have a baby and you’ve put on some weight.
The only thing you can really do, though, is talk to him about this and ask questions. No human body is perfect – has he put on weight since you met?