Hello VSteven509!
Don't ever think for once that God is not able to forgive you of your sins. Lets see what the Good Word says:1 John 1:9 - If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.
Also it is definitely a sin, if you lust after another woman regardless if it is physical, you have lusted after her in your heart which is adultery in your heart. Pray to the Lord and ask Him to remove this Bondage of Lust from within. Stay Strong.
God Bless!