My girlfriend's weight gain is affecting our sex life....

So.. my girlfriend and I are in our late twenties (lesbian, both female).

We've been together for almost two years, and recently I've become more and more aware that our sex life is simply not what I hoped it would be. She's has gained 70+ pounds since we met, which has greatly affected her body image.

She has stated it was "happy weight" gained from being in a healthy, happy relationship. She's praised me for making her feel loved and accepted as she has gained weight. While I'm happy she feels secure in my love, I also see how unhappy the extra weight makes her.

I've seen her hysterically cry in the goodwill parking lot as she gave away clothes that no longer fit, every old sentimental pic of us together I find, she says "i was so hot and skinny then", she is starting to have back issues, hip issues, knee issues, and is on the cusp of becoming pre-diabetic via her last doctor's appointment. Every event we go to becomes stressful as she can't find anything to wear, and then when we get to the event she is often in a bad mood for the first 1-2 hours, as she recovers from the getting-ready-stress.

Now listen. I'm not an asshole. I would never in my life tell her she needs to lose weight. I'm also a woman, so I 100% understand beauty standards and the crazy societal expectations that are forced onto women. I empathize with her struggle.

But here is my issue.. she never wants to have sex anymore. After noticing things tapering off the past 6-9 months, and her general disinterest, I obviously asked what was up. She stated it's because she feels insecure with her body, and that prevents her from feeling 'in the mood'.

I told her I understood and would never want to have sex if she wasn't 100% feeling it. Reassured her I think she is beautiful inside and out, but I did also mention that intimacy is important to me, and having sex with my partner is something that I want, and we should work on it together. Even if that's just once a month, I kinda need that deep connection to feel close, bonded, and 'safe' within a relationship, ya know?

I've always had partners with high libidos. I've never had to suggest to anyone that we try to have more sex, so this is unfamiliar territory to me. And i've been treading very lightly and carefully, as I don't want to make her feel worse about herself. I also don't want her to think all I want/think about is sex, but I can't deny that I value sex in a relationship. I'm human, after all.

So one problem here is the lack of sex/initiation on her end, but another (and this may be a more lesbian-specific issue), more often that not when we DO have sex, she'll let me finish her off but won't reciprocate. Which she says is because I 'wore her out' or 'did such a good job', but it makes me feel used and resentful. It's like my needs don't matter to her. She'll feel bad about it in the moment, and even say she'll 'finish me first' next time, which rarely comes to fruition.

She wants to move-in together within the next year or so, talks about marriage and wedding plans, spends 3-4 nights a week with me, but honestly, this is a deal-breaker if something doesn't change. I do so much work to try to make her feel sexy and appreciated. And I feel like she doesn't care at all if my sexual needs are met. She's caring and wonderful in other ways, but we're seriously lacking intimacy and she seems to be unwilling to do anything on her end to mitigate the self-esteem issues she's facing.

I fear if i said something beyond our previous discussions, it would be taken the wrong way and only hurt her. I fear if I don't say something, I'm going to harbour resentment and eventually leave out of frustration, which would blind side her. We have a pretty happy relationship outside of this.

Reddit.. please... I need your advice. How do I have a gentle conversation about this, where I can express the importance of my needs without sounding insensitive to her struggles? She knows she has gained weight- I don't need to tell her that. But I feel I need to express that her unwillingness to make steps towards progress (whether that be losing weight OR accepting herself as is) is putting a strain on us, and I regret to say I'm growing more distant and apathetic by the day. Part of me feels like it would be such a dumb thing to break up over. Part of me imagines being in a sexless relationship for the next 50+ years and.... I can't.

How do I go about this conversation?

EDIT: Thank you for all the thoughtful advice. I'd like to add that she does have a thyroid problem, which is partially to blame for weight gain, but I'd be lying to say she always eats appropriately. She does over eat at times and expresses guilt about it after. So food addiction/binging is for sure a part of the equation. Which I'm sympathetic to..... to an extent.

She had a gym membership briefly, and I would go as her guest, but that was short lived and she started taking yoga classes instead. Which is better than nothing, but yoga isn't really burning off calories like a treadmill or stairclimber would do. Also, when we *would* go to the gym she'd spend half the time on the elliptical and half the time using the arm/back/leg machines, which confused me, as she's not really trying to build or tone muscle. Maybe this suggests she is less-educated about how to burn fat effectively, as I'd think cardio would be more beneficial for her than moving weights around stationary. I didn't say anything though, as I was just happy she was going at the time and didn't want to be a know-it-all or add criticism.

We both have individual therapists, but I have noticed she hasn't gone to her appointments in the past month, which likely is due to finances and her having to pay for car troubles, etc. So I haven't mentioned it, but I will certainly encourage her to continue therapy when I bring this to her attention. If nothing changes after this, I may suggest couples therapy, but depending on how seriously she takes my concerns, it may be time to move on. Sigh.

After reading the comments I have a clearer direction on how to lead this conversation with kindness, and I will make the focus on the intimacy issues and reciprocity, more so than the weight gain.

I'm anxious for the talk, but also confident in my needs being met moving forward. I don't get on reddit often, and I honestly don't even vent to my friends much, so this has been therapeutic for me to work this out with some input from kind and insightful internet strangers. Thanks for taking the time to leave some words. I'll update this post when we do have the talk. I'm just waiting for the right moment, most likely this weekend when she comes over.

I expect she won't initiate- and Sunday morning over coffee and I plan to let out my feelings and concerns. Thank you, thank you, thank you again,