I have been baptized into the Coptic Church since April 2003, my studies finally leading me to believe that Orthodoxy is the way I want to follow Christ, the closet way. My girlfriend who is the most godly Christian I have ever met and going to meet is not an orthodox; and from what I learned about the Coptic Orthodox belief concerning intermarriage, getting married to her will deny me partaking of the Holy Mystery of Communion. What do you think is wiser to marry someone that you know will be a solid wonderful Christian wife, or marry someone who you do not really love, just because the church says so? Like a marriage of convenience?
There is an option you didn't mention, getting your girlfriend to become Orthodox. Have you considered this option and have you talked to her about it. Did you express to her that your faith is very important to you and that you became Orthodox because you believe that this is the WAY?
Choosing to deprive yourself of the Body and Blood of our Lord Jesus Christ and deviaing e from the way to eternal life is totally up to you but remember "he who loves father or mother more than Me is not worthy of Me. And he who loves son or daughter more than Me is not worthy of Me" (Mt 10:37).
Talk to this girl frankly and explain to her the whole situation giving her your reasons for choosing Orthodoxy in the first place and the consequences of marrying outside your Church
Discuss this matter with your confession father and maybe he can sit with the girl and give some classes on Orthodoxy.