It's no longer necessary to follow the Mosaic law because Jesus fulfilled the requirements of the law and paid for the sins of his people. If you would like an in-depth answer, google: why do we no longer follow the mosaic law.
> Bring ye all the tithes into the storehouse, that there may be meat in mine house, and prove me now herewith, saith the LORD of hosts, if I will not open you the windows of heaven, and pour you out a blessing, that there shall not be room enough to receive it.
And not to mention that the New Testament doesn’t say anything about homosexuality.
There is a big difference between heterosexuality within a loving, monogamous relationship and without such, just as homosexuality within a loving, monogamous relationship and without.
As long as homosexuality is monogamous and within a loving relationship, it is no different, meaning no more or less sinful, than a monogamous heterosexual relationship within a loving relationship.