I apologize if this is disorganized, I am just really confused and feeling lost

So my girlfriend and I have been together for 1 year and 8 months now, we’ve known each other for over two years though.  We’re both college students in our early 20’s, we attend separate schools and see each other 3-4 times each week.  After being with her for about 6 months I started having somewhat doubtful emotions about our relationship, this was right around the end of the summer last year which we spent apart (we started dating in February).  About a month into the semester I cheated on her (yes I know what I did was horrible, and I regret what I did deeply, I apologize if this offends anyone reading this) .  I didn’t tell her for a couple months, I was fighting with deep emotions of what I thought I wanted and how I felt about my girlfriend the whole time.  When I finally told her I took all the blame, and I made sure she knew she didn’t have to forgive me and if she wanted to end things I would’ve understood.  When I told her I decided I wanted her and loved her and didn’t want to lose her, she made the decision to forgive me and that we would work on our relationship moving forward, and now for the past year, almost, since telling her we’ve been spending more time together and our relationship has been progressing at a healthy rate.

Now, during all of this, since the time when I started having doubtful emotions, like 6 months after we started dating, I have had on and off feelings that our relationship doesn’t feel quite right, something just feels off.  I don’t have these feelings all the time, and the intensity of them is varied, they’re usually weak and easily ignored to where I’m actually considering that maybe this relationship isn’t quite right.  And I’m currently having them now and this is the strongest I’ve ever felt them and I’m actually considering ending the relationship.  I assumed that these feelings where just twisted from when I cheated and that this is not how I actually feel, but now after a year, I was hoping that I’d feel much more much better in our relationship, but I feel they’re only getting worse.

There isn’t anything seriously wrong with our relationship as far as I’m concerned.  We’re both understanding of each other.  We’ve had our fights like any couple has, and for the most part we’ve fixed or helped whatever was the main concern of the other after these fights, and we usually only have them maybe once a month.  The only thing is one thing almost always comes up with these fights and that’s our sex life.  We’ve never had intercourse for somewhat medical reasons, but we’ve done almost anything else in the books.  We have on off periods where we might do stuff like three days in a row, but then most of the time we might do stuff like 1 or 2 days every couple weeks.  This is mostly my concern as I’d like to do stuff more often, there’s things that I have an interest in trying/doing that she really doesn’t like to do, but most importantly she just doesn’t seem extremely into doing stuff.  She rarely initiates it, and when we are doing stuff she just seems almost lazy or lackadaisical about it.  Every time we’ve had a fight this almost always comes up, and I just feel it’s always a repeat of the same argument.  Plus I just feel like I shouldn’t be holding sex this important and I always feel terrible about complaining about it, and she tells me that me complaining about it just makes her want sex less and that I need to stop worrying and complaining, but then when I don’t for a couple months, and nothing has changed at all, I can’t help but worry and bring it up.  I’m not sure if I’m being crazy and maybe I just want sexual activities too much, I understand that her and I aren’t always going to be in the mood at the same time, but I just feel like she is never in the mood or never really interested in doing stuff.  Whenever we make plans to do stuff, about like 50-75% when we made plans she’ll tell me that she’s not in the mood or too tired and then will promise we’ll do stuff the next morning and then we don’t.  I just feel bad about wanting sex as much as I do and I don’t know if I’m wanting it too much or if I’m actually fine and we just don’t have sex as often as we should?

I only talk so much about that because it’s the one thing that after a year I’m still not exactly happy with our sex life and almost always comes up with our arguments and doesn’t seem to be changing at all.

I’m also confused if there is a specific reason why I might be doubting our relationship or if it’s normal to have these thoughts and I’m just thinking to far into them?

I have shared this with my girlfriend, twice now actually within the past two months, and now I think we are both going to try couples counseling to try and figure out what might be going on.  I’m just hoping to get some different opinions and advice from you guys.

Sorry for the long post and I thank all of you for reading it and giving me advice.