My boyfriend made me feel insecure

Up until last night, my boyfriend has been near perfect. We have our arguments here and there but it’s never anything we can’t move past. But yesterday after work we went out. I had two drinks and he had one, so I really don’t feel like this argument was fueled by alcohol. Basically he told me he thinks I have a beautiful face and a great personality, but since I have gained some weight, he is no longer attracted to my body. He said he is still attracted to me as a person, but just not my body. I have a feeling this is him projecting his own insecurities onto me, as he has been really struggling with his own body issues but I still can’t help but feel ashamed I guess. I do have self worth, but I really love him. We are planning on getting married here soon. This is super out of the blue and I just can’t get past it. I told him if he wants this to work, he needs to figure out how to talk to me in a healthy way and see a therapist. But I am scared this wasn’t a projection of his insecurities and he really feels that way about me. Note, I am 5’8 and about 160 lbs. I don’t feel like I am fat, but he kept saying the word fat.