After yesterday I have a major decission to make. The reason being my 23 year old stepson Jack purposely showed me his semi hard cock, when we were sat out in the garden subathing. We'd all been drinking and were joking about their families trait of the males having large penises. His father had gone inside to the toilet, Jack called my name and as I looked round I saw him with his shorts pulled down and he was holding a very thick meaty looking cock. My husband has an eight inch thick cock, his son Jacks cock was bigger by at least an inch or two and it wasn't fully erect. When my initial shock wore off I asked Jack what he was doing. Jack replied by telling me he'd always fancied me and if I ever wanted his dick, he'd gladly fuck me. Later in the kitchen once again alone, I let Jack put his hand up my short skirt from behind as I was doing the dishes. I didn't stop him as he massaged my pussy through my panties and then moved my panties aside to insert a finger into my wet pussy hole. I stood taking pleasure from his fingers until I heard his father walking in from the garden, only then did we stop. Before he left to go back to his apartment, Jack asked me if I'd like him to replace the fingers for his cock, in an instant I said yes. Smiling he asked me text him when I could call by. I'm off work all next week and Jack knows it. I have to decide if I should follow my hunger for his massive cock, or stay faithful to his father, my husband.