"Even though I feel lonely in my current relationship"
Even though my DxH cheated on me many years ago, and left me to live with (and subsequently marry) his mistress, I do actually feel sorry for you now @Sonygirl23
Feeling lonely whilst in a long term relationship is a crap feeling - I know because I have spent many, if not most of, my current marriage to my DH, feeling exactly that.
There are many reasons why I feel like this and I don't think that they can all be laid at my DH's feet, or even my DxH's feet for that matter. I did feel loved (maybe even very loved) throughout my childhood, but I have just thought this very instance, that subconsciously I may have thought/do think, that that was because I was their child. You are supposed to automatically love your child, but I now realise that there was nothing personal about my characteristics that they loved me for, or were proud of me for.
Gosh, sorry, I am just having a selfish moment of feeling very sorry for myself, and having tears in my eyes, back to you OP.
I feel that you really need to address the loneliness you feel in your marriage, both singular and couple counselling should be helpful in doing that - if you can access them. If after a lot of deep thought, and hopefully discussions, with your DH, you realise that a lot of your feelings of loneliness are down to the relationship you have with your DH, and if after having talked about this with him, and hopefully counsellors, you realise that nothing will change within this relationship with your DH, then it is probably time to re-evaluate your partnership and to probably break up with him.
I cannot advocate spending the rest of your life with him, I have no choice but to do so in my marriage, and I do still love my DH very much, but I seem to have to "fight" (emotionally, not physically) with my DH every day, just to remind him that I do actually still exist - please don't let happen to you in xx years down the line.