I did not know this until a couple weeks ago, but it is totally possible to have completely normal sex (that's awesome for both partners) despite phimosis. I had thought phimosis caused either painful sex or premature ejaculation (or other problems). Apparently while it can cause problems for some men, it does not always. So you don't necessarily have to correct it with stretching (or anything) just to have normal sex. If your phimosis doesn't interfere with your sexual and other functioning, it does not necessarily matter too much.
But the other bad thing about phimosis is that it can also make it hard or impossible to clean the inner parts of the penis, which can make infections more of an issue if you ever get one. Yeast infections can actually cause the foreskin to grow tighter making phimosis worse (or causing it as it often does in older diabetic men). And because phimosis makes it hard/impossible to clean and dry the area behind the tight skin, it can make it quite a bit more difficult to get rid of a yeast infection if you ever get one.
If it were my penis, I would definitely try stretching because it helps to keep it clean. But if the frenulum is also short and tight, the stretching can take a very, very long time (many months). There's a non-excisive (no tissue removed) operation to lengthen the frenulum (frenuloplasty). I might consider this for tight frenulum if the (painless) stretching still doesn't get anywhere after months of trying (which is rare). Whatever stretching you do, you have to do it so slowly and gently that there is never any pain at all. Pain indicates tearing which just makes it take longer. For more about foreskin stretching, see the thread Stretching To Fix Tight Foreskin (Phimosis).
I agree with Sadhu about circumcision. It's incredibly desensitizing and irreversible. I would not recommend it at all. There are many much less severe options (even if the foreskin is causing problems).