This is not meant to be a contentious post...I know I am going to get killed by the militant fascist faction here...
Are you drastically more overweight than before your pregnancy that ended over 2 years ago? If it is just a few lbs. then disregard what I am about to say...I don't know so I am going to speak hypothetically here...general terms...
When either spouse "lets themselves go" physically, it tells their partner that they are not important enough to make the effort for. Not just weight, but how someone dresses, their personal hygeine, or even the sloth that can come with settling in. I understand that wieght from pregnancy doesn't come off easily. But let me ask you ask question...If your childs life depended on you getting back to your pre-birth weight, could you do it then? I bet you could. Yes it is difficult. It is not impossible, and chances are that you already posses the knowledge you need to lose the weight. What is your excersize routine? Do you have one? Many people buy diet books as an excuse to stay fat, not to really lose the wieght.
Men and women both need to feel that they are worth their partners effort.
My detractors will spout the cliche'd quotes like "If he truly loved you, your weight wouldn't matter" But the reality is, He could easily say that if YOU really loved HIM, you wouldn't take him for granted. Chances are he does still love you, and want you, but he has every right to be with the woman he married, and if that is not who you are now, then you have to address that. He can't be a totally shallow jerk either, but two years is a long time.
Lastly I will say this, When *either* spouse takes thier other half for granted, it is as much infidelity than if they had flirted with intention......some people "cheat" with the hostess in the diner, others cheat with hostess twinkies.