Men can be very disappointed in how women stop taking care of themselves after landing a man. Start working out and dressing nice. Be nice to him, never sarcastic. Appreciate it when he does nice things. Flirt with him. And yes, work out and eat right so you turn heads ... including his.
I'm sorry, I find the previous comments rude among other things. You shouldn't have to change how you act for him, act like you always do, like who he fell in love with. It's easy to place blame on the woman and assume she's "let herself go" after "landing a man" when that's not what sounds like what is going on.
You've put on weight over 2 years, been married 2 months, so I doubt you've put on much weight since your wedding and if he was attracted 2 months ago, I'm sure he is now. Being a newlywed is a stressful time for both, it's not unusual for both to gain weight (I gained ~15 pounds, so did my husband, it is what it is) and also due to stress, for libidos to decrease. Give it time, communicate, do favors here and there that he would appreciate and help lower his stress, flirt, and if you're trying to initiate sex, make sure he's getting the signal. Of course take care of yourself, but do that for you. He'll come around. Try spicing things up, too.