To the OP,Here’s what you do:
I doubt you will be allowed to receive communion at the Orthodox Church (such things happened in Russia - and perhaps even today - but only in remote villages where it was obviously difficult or impossible for Catholics to have their own church). Tell her how important the Eucharist is for you, and since you won’t be able to receive it at the Orthodox Church, you need to go to a Catholic Liturgy as well to receive communion.
Blessings,
Marduk
You should go to Holy Communion as often as possible, and you should try every day to make yourself more worthy of that great Sacrament. Think of it! To receive your God and Saviour into your soul, and to be united with Him, as the word communion means! The early Christians used to go to Communion very frequently. The Church requires us to go to Holy Communion at least once a year, but we should not be satisfied with doing merely what is necessary to avoid mortal sin. Do we try to keep away from persons we love? Then if we really love Our Lord should we not desire to receive Him? All good Catholics should go to Holy Communion at least once a week, on Sunday. Persons wishing to lead truly holy lives should go to Communion more often, or even every day.
Catechism of the Council of Trent:Catechism of Pius X said:54 Q: Is it a good and useful thing to go often to Communion?
A: It is an excellent thing to go to Communion often, and even daily in accordance with the desire of the Church, provided we do so with the requisite dispositions.
Based on your description, I am confident that a polite explanation of the importance of being able to receive Holy Communion while you are visiting will alleviate any concern. As for the rest, by all means attend an Orthodox Liturgy while you are there in addition to Catholic ones. I am sure it will be an edifying experience.The Church Desires The Faithful To Communicate Daily
However, let not the faithful imagine that it is enough to receive the body of the Lord once a year only, in obedience to the decree of the Church. They should approach oftener; but whether monthly, weekly, or daily, cannot be decided by any fixed universal rule. St. Augustine, however, lays down a most certain norm: Live in such a manner as to be able to receive every day.
It will therefore be the duty of the pastor frequently to admonish the faithful that, as they deem it necessary to afford daily nutriment to the body, they should also feel solicitous to feed and nourish the soul every day with this heavenly food. It is clear that the soul stands not less in need of spiritual, than the body of corporal food. Here it will be found most useful to recall the inestimable and divine advantages which, as we have already shown, flow from sacramental Communion. It will be well also to refer to the manna, which was a figure (of this Sacrament), and which refreshed the bodily powers every day. The Fathers who earnestly recommended the frequent reception of this Sacrament may also be cited. The words of St. Augustine, Thou sinnest daily, receive daily, express not his opinion only, but that of all the Fathers who have written on the subject, as anyone may easily discover who will carefully read them.
That there was a time when the faithful approached Holy Communion every day we learn from the Acts of the Apostles. All who then professed the faith of Christ burned with such true and sincere charity that, devoting themselves to prayer and other works of piety, they were found prepared to communicate daily.