How long have you been having sex? My bf and I had sex for about 4 months before I learned how to come (we were each other's firsts, pretty much; same as your situation). It only really happened once I started to believe I would never come, and thus stopped worrying about it.
I usually only come through oral. It takes a lot more work on his part for me to come while he's inside me... it does happen, usually when I am on my stomach and he is lying on top of me, reaching around with one hand to stimulate my clit. But sometimes we are just too impatient for that.
Now, two things I have to ask you:
1) He said you had "puppy fat?" If you ask me, that's really not a nice thing to say. I would probably raise hell with my bf if he said something like thatl. Have you told him how that makes you feel, especially in regards to sex and your body?
2) From where/whom are you getting your info on BC? A condom is really not enough protection... the failure rates are surprisingly high given common use. I would be using another form of BC if at all possible, barrier/hormonal or otherwise. Personally I was on the Patch for a year and then the Ring for another year now, and have never gained weight on either (unless you count an increase in boob size, but that's not all bad!).
The only BC I have heard is really bad for weight gain is DepoProvera (the shot)... but maybe other ladies can respond to this with their own experience.
3) Have you gotten a pelvic exam from your gynecologist since you started having sex? (More importantly, have you talked with a doctor or health care provider about birth control options?)