There's no reason to feel guilty for natural sexual fantasy and expression.
Many heterosexual women have discovered sex with another woman works perfectly for them.
Many lesbians are into vaginal penetration and some love to fuck their girlfriends with a strap-on penis.
I'd rather deal with a person who has a good sexual connection to themselves than an experienced but mindless one who is very social.
It's not about your partner. It's about the type of clitoral stimulation you're experiencing with your partner.
We rarely can experience sex between equals.
You should experiment and see where it leads.
I'd advise all young women and men to experiment with both sexes before they commit to one specific sex style.
Anyone who delves into sexual pleasure will have had many varied sexual experiences with both genders.
I'd suggest you stop talking about your desires to be sexual with a woman and just do it.