masturbation.

I feel really bad. My s/o and I have sex like every other day and this last week he's worked every day so we haven't had time. Well tonight I got horny and I masturbated. But when I came I thought about his ex girlfriend?? I'm pansexual. When I masturbated I was thinking about him. Like the emotions I get when we do it and everything. But when I came I thought of her. Is this normal? I feel really uncomfortable with myself right now. I feel like there's something wrong with me.