Thanks all for the replies. I think later on I’ll start individual threads on specific topics, instead of the multiple topics being discussed in this one thread (not that it’s a problem, just to be more organized and be able to respond more coherently,

).
So I haven’t discussed my dilemma with any LDS friends yet. I did discuss it with a coworker who is familiar with LDS beliefs and practices (she had a LDS roommate in college and went to church and other activities with her sometimes). After our discussion, she said “Well, Mormonism is tough to swallow, but you already swallowed it!”.
I think that shows how much of a change it would be for me to go from a believing Latter-day Saint, as someone that everyone knows is a Latter-day Saint, to not. I also think, as I’ve mentioned before, that it would be very difficult for me to leave. Not that they would hold me hostage or say “no, you’re not”. Perhaps it’s more of a mental thing for me, but I don’t know if I have it in me to sit down with my bishop and say “I don’t have a testimony anymore, I don’t think the Church is true or what it claims to be, and will no longer be a member”. It would be difficult for me to leave because everyone knows that I was an active Catholic before, and that it was difficult for me to make the decision to become LDS. Sharing your testimony all the time (and really believing it) that you KNOW the Church is true, that Jesus is at its head, Joseph Smith was a true prophet, etc, and then saying “actually, jk jk”, that is difficult to imagine. I guess I’m just thinking about how it looks from the opposite side, especially since many look to me as an example (compounded by the fact that I’m Elders Quorum President too), love my testimony, think I’m strong, etc.
Here are a few areas that I’m thinking about as causing difficulty (and would probably be best for a separate thread each:
The Nature of God
I have no problem believing that the Father, Son, and Holy Ghost are distinct Persons. They are not each other. I think that both LDS and traditional Christians can agree on that. With the LDS, I have serious issues with the belief that God the Father was once a man that progressed to God. Now, some LDS will state that while they do believe that, they believe that the Father remained Divine during His mortal existence, just like Jesus Christ did. The problem is that various apostles and prophets have stated that the Father
progressed to Godhood. I don’t necessarily have a problem with the Father having a body, unless He always was embodied (yet we always talk about the Father being an “exalted man”, having a “resurrected body”, etc.). Also, the belief in an infinite regress of Gods (which logically comes from the belief that the Father may not have always been God) is an issue.
I find that it makes much more sense, and is consistent with the Biblical and historical (Jewish and Christian) records, that God has always been God, did not progress to being God, etc. With this, there is of course a difference between belief on the pre-mortal existence of Jesus Christ. LDS believe that Christ was the Firstborn Son of God (literally), the firstborn of all of the Father’s (and Heavenly Mother’s) spirit children, including us. LDS believe that we are
all eternal in the sense that our core, our intelligence, has always existed. However, we were “created” (organized) by the Father, including the Son. So in a sense, there was a time when the Son did not exist as the Son. I have difficulty with that.
Revelation
Revelation from God is an important topic for me, and of course is a point frequently brought up by LDS. I believe that God always speaks to His children, and has never stopped doing so. I think that many LDS confuse the traditional belief that public revelation ended with thinking that traditional Christians believe that God no longer speaks. Obviously that isn’t true. I know that Catholics/Orthodox believe that while public revelation (i.e. revelation from God pertaining to what is necessary to be saved, if I understand it correctly) ended with the apostles, God still does speak to His children, we can receive inspiration and guidance from God, and God leads the Church (whether Catholic or Orthodox, in their belief) through the Holy Ghost. It also seems that Catholics and Orthodox not only accept the belief that there have been prophets after the New Testament throughout time, but there have also been prophetesses as well, which, if I remember correctly, is consistent with the Bible.
Whenever someone asks me what is unique about LDS, I always bring up our belief in prophets, and that prophets and apostles lead our Church. They then ask “what was the latest prophecy?”, which causes some difficulty. I could point to GC addresses as inspired teachings, yet they aren’t really that different than what Catholic/Orthodox leaders say in their inspired messages. We also haven’t update the D&C lately (and the last two updates were on Plural Marriage and the Priesthood restriction), though we talk about continued scriptures.
The Sacrament/Eucharist
There is of course a clear difference in the LDS vs Catholic/Orthodox understandings of Communion. It is much easier to accept the LDS view. However, with the Bible and the earliest post-NT Christian writings, it seems as if the Real Presence viewpoint has always been held. It is curious that all of the most ancient Christian churches, no matter where in the world they are (Greece, Rome, India, Egypt, Ethiopia, Armenia, Jerusalem, Antiochian, etc), accept belief in the Real Presence. That is difficult to dispute.