I am posting here as I am in an age gap relationship, and other subreddits seem to focus on mainly that, and not the issue at hand.

I (39M) have been with my lovely girlfriend (25F) for about two years now. She has been there through thick and thin (I struggle with addiction and have relapsed during our time together about 4 times, and she has taken care of me every single time). I love her to pieces, although at times I am not great at showing it. She tends to be very affectionate, compliment me a lot, whereas I am a bit more reserved.

About a year ago, we traveled to Slovenia together for a getaway. Whilst we were there, she pointed out jokingly how the women were dressed really well whereas their partners were wearing cargo shorts. I jokingly told her back that if we ever broke up, I would move there. I added even a worse comment by wondering how gorgeous of a woman a bloke like me could get.

She went silent. The next morning on our holiday after this she showed me her outfit, which was an all-black tight outfit, that showed her belly. I got worried that due to some dysmorphia issues, she may freak out when she sees her belly fat in the photographs, and I told her to cover herself up. She spent the rest of the holiday in tears.

Ever since then, I have occasionally made nasty comments to her about her looks and her achievements/career (she is very insecure about her job, as she recently left academia), but only during my relapse time. I have not said these things sober, and never would.

Today we went to the gym together, and she went quiet after she came for me for reassurance about her gym wear and I encouraged her to wear a loose t-shirt instead of a sports bra. She was NEVER like this prior to my comments I made in Slovenia, but ever since this she has taken everything to heart, gets quiet and every time I get even a bit frustrated or angry she flinches like I am about to do something bad/scream at her.

I truly love her, and know I cannot take back what I said. She also seems to be caught up on these things, which I understand, but I have also complimented her a lot. She has been dressing better, and taking great care of her skin, and I compliment her every evening on these things. I also tell her that I am proud of her and her work (teacher), and find it very admirable. Things just are not the same they were before my thoughtless stupid comment. I realise that I am a dumb man, and need to make things right. She is the most caring, selfless person that I know, and she deserves to be happy and feel good about herself. What the heck do I do here?