Help ! Relationship issues...maybe?

My boyfriend and I have been dating for 8 months. It doesn’t seem long to most but our relationship has moved fast. We live together now for 3 months and I have twin girls from a previous relationship. My boyfriend takes the role as the girls dad due to their biological father not wanting anything to do with them he signed over his rights and I have full custody of the girls. Well everything between my boyfriend and I are going great. But here lately I have had no sex drive. Everything he does irritates the hell outta me and he’s gained weight. I’m not attracted to him physically anymore. We

Have a great emotional connection but he drives me crazy. I love him to pieces. Is there anyway I can talk to him about this without it hurting his feelings? Is there anyway I can help myself become more attracted to him physically? I want to be with him and I feel like an ass because I’m saying I’m not physically attracted to him anymore. What do I do? Looking for help and advice!