Need advice

I need advice I've been with my boyfriend for 10 months I love him and everything is good but our sex life. I'm a very sexual person and I can do it every day but he's not at all like me. He always tells me how beautiful I am and how attractive he is to me. I can walk around in his shirt and he will just get hard. But when it comes down to actually doing it he turns me down. I honestly don't feel like he's cheating but I do think he may have a issue getting it up. Should I talk to him about it. How can I discuss it without putting him down