5'3" and 150 lbs. is not super overweight, but it is not helpful in getting pregnant to be over your ideal weight by more than ten pounds. To get pregnant the natural way, you might try dropping just a bit of weight and exercising a little more, and taking iron. All of those things will help.
My question is, if you don't like sex and have an aversion to it, realistically, how long do you think this marriage is going to last? Not a lot of men out there are interested in a sexless marriage in the long term. (Of course, exceptions would be if a woman is married to a man who is also not interested in sex, or is using her as a cover for gay activities that would not be acceptable for whatever reason.) I am just puzzled and a little worried for a child, that you would be willing to go through the cost, stress and pain of IVF, if there is a good change the marriage will not last. Don't you think that is sort of unfair to the potential child? Kids really, really like having more than one parent, and it is easier on the parents as well, since one is not always on duty all the time if the other is there.
typo -- chance not change
There are some studies that suggest a woman's orgasm makes her more fertile. Honestly it sounds like bull, but even if it's not it wouldn't surprise me if your disinterest in sex is causing issues. Because you are over 30 your doctor will probably be very willing to give you information (specific to your circumstances and country/state) about IVF and other methods for conceiving.
Although before you do this I would STRONGLY suggest asking your doctor about potential causes for disinterest in sex. I know that some medications, depression and other hormonal imbalances can cause a lack of a sex drive. It may be worth looking into to make sure that there is no underlying health issues before you try to conceive.
Really a healthy marriage isn't necessarily defined by the amount of sex. My in laws have had almost a completely sexless marriage for YEARS actually probably over a decade- they got separate rooms over 15 years ago. They still have a very loving, compassionate, communicative, and what I would usually consider a healthy marriage. My grandparents on the other hand are a polar opposite and they've almost gotten divorced 3 times in the 28 years they've been married. They had an extremely volatile & reactive relationship for almost 20 years. Personally I couldn't handle a sexless marriage, I think I'd go nuts :D But never be too hasty to believe the social norm is ideal.
You know that their marriage is sexless? Or do you just know that they have separate bedrooms? And how old are they, and does he snore like crazy (my uncle snores like a dying moose, and my aunt sleeps in the guest room). The o.p. doesn't sound old enough to be anyone's in-law, so I was assuming a young husband also. I am not saying the social norm is ideal, I'm just saying that if a woman says she does not want sex at all and doesn't mention in the next sentence that her husband feels the exact same way, I would look at the question of whether the marriage is likely to last over the next 18 years or so, which is when she would want both parents to be as present as possible in the child's life.
I know that my in laws almost never have sex because I had an open discussion with my mil about sex toys. (She's just in her 50's.) It was mainly because of fil lack of sex drive, he's just never interested. The separate beds came out of sleeping better apart and needing to be up for work at different times. I knew about my grandparents because I lived with them for a time while at Uni and I actually asked my grandma after her surgery that removed a tumor, most of her rectum, some of her bladder, and some of her vaginal area what her and my grandpa did for sex.
I do agree with you that there needs to be some sort of intimacy in a marriage or relationship and if the lack of a sex drive interferes with that it could be a problem. Feelings of unsatisfaction can lead to those of resentment and bitterness. I just have to disagree with the importance of sex because I know my husband and I don't see eye to eye on it, but I can't believe for a second that could ever condemn our marriage.