^^ Good advice.
...You need to clear your thoughts, then drift off.
Hey Carlos -
Good start from the two posters above. Let me add to the ^^ advice and help you learn to clear your mind:
Jack off. Seriously, man. Jack off.
Your sidebar profile says you are in an open relationship. I don't know if that means you live alone or together. But, if your other half lives and sleeps with you, tell them you're going to bed - alone. And stress the "alone" part and tell them they can't come in for an hour.
About 30 or 45 minutes before your normal bedtime, go into the room, shut the door, get naked, turn off the lights and stretch out on the bed.
Slowly and gently massage your temples and forehead. Work your way down to your neck, then your chest. Focus your thoughts on the sensations and feeling of your hands caressing your body. Breathe slowly and with purpose. Work your way down to your abs... then move to your inner thighs, just allowing your fingertips to barely brush against your balls. Keep your hands off your cock right now. Play with your balls and massage them for a while. Think about how good it feels to gently squeeze them and roll them around in the palm of your hands... Then move up to lightly stroking your fingers along the shaft of your dick, tickle the underside of the head. Bring your thoughts to focus on this core place of your being. Wrap a hand around your shaft and slowly stroke up and down. Don't think about increasing the pace, just allow it to happen naturally. When you cum, milk your shaft from base to tip with each spurt. Keep focusing on the sensations of it, keep slowly stroking yourself until your hard-on wilts completely. Then place your hands on your stomach or to your sides. Take one last deep, deep breath, and let your whole body melt and sink into the mattress as you exhale.
Do not, I repeat,
do not attempt or think about cleaning up. It'll dry and you can shower in the morning. If that doesn't suit you (some guys just can't lay there drenched in their own cum), then in
slow, effortless movements, massage it into your skin until it's completely dissipated.
This is an exercise I employ when I have difficulty in getting my brain to shut off, to stop thinking about whatever family or work issues have invaded my sleep for a few days. I tell my wife I'm going to bed - "alone" and she knows to give me about an hour before she comes in to bed. Once I cum and sink into that mattress, I drift off almost immediately and sleep like a baby.
It may sound silly, or overly simple, but what have you got to lose??? Give it try.