"One cannot declare a marriage to be extinct on the pretext that the love between the spouses is "dead." The indissolubility of marriage does not depend on human sentiments, whether permanent or transitory. This property of marriage is intended by God himself. The Lord is involved in marriage between man and woman, which is why the bond exists and has its origin in God. This is the difference."and....
"If we open the Gospel, we find that Jesus as well, in dialogue with the Pharisees regarding divorce, alludes to the pairing of "divorce" and "mercy" (cf. Mt 19:3-12). He accuses the Pharisees of not being merciful, since according to their subtle interpretation of the Law they had concluded that Moses had granted a presumed permission to repudiate their wives. Jesus reminds us that the mercy of God stands against our human weakness. God gives us his grace so that we may be faithful.
This is the true dimension of God's mercy. God forgives even a sin as grave as adultery; nonetheless he does not allow another marriage that would cast doubt upon a sacramental marriage already in existence, a marriage that expresses God's fidelity. Making such an appeal to a presumedly absolute mercy of God is equivalent to a play on words that does not help us to clarify the terms of the problem. In reality, it seems to me that this is a way to keep from perceiving the profundity of authentic divine mercy. "
There is only one way to keep marriage safe, and it has nothing to do with the behavior of homosexuals, or public recognition of their relationships. It is to adhere to God's plan for marriage, and the reality vanishes without fidelity and indissolubility.
I recommend reading the whole article.