Insecure

Me and my So have a 8 month old son and have been together since he was born but I'm still very sexually insecure and I'm scared that I couldn't lose him because of that he says i wong but what can I do to be more okay with myself sexually. It's really sad I fantasize about all these fun things we could do but when it comes down to doing them I just get way too shy and I'm insecure in all aspects of my life which I just don't understand it I don't understand why I'm so insecure