I can't make my girlfriend cum. I've been able to make the majority of girls I've been with cum, but not this one.

She says she doesn't care and that she only cares about me feeling good, which I can tell she means, but I still feel inadequate.

I can tell she loves that I completely dominate her and take complete control. She gets really turned on but it never ends with her cumming.

If this was some random girl, I wouldn't care. But I feel that I should be able to make my girlfriend cum at least occasionally.

She says the sex feels really good, and that it feels great when I finger her but when I use my mouth it doesn't feel great. Any advice on how to proceed?